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Attention: McKinsey applicants…
I’ve Uncovered The Best Way to Crack the McKinsey PSG That Almost Nobody Knows About…
To give you the McKinsey offer you want!
From: Francesco Rieppi
My name is Francesco Rieppi, and I’m the #1 case interview coach in the world by number of certified coaching sessions and 5-star reviews .
Yes, that’s right – in the world 🙂 . Here is the proof from PrepLounge.com (you can click on the image to check!):

I am an ex-BCG consultant and, over the past 9 years, I have helped hundreds of candidates in their preparation to land offers at McKinsey.

However, a few years ago McKinsey changed the rules of the game…
They moved from the PST to the McKinsey Problem Solving Game and the candidates I helped started to panic as McKinsey claims there is no way to prepare.
I didn’t know what to do to help my candidates… but finally, after tens of hours of research, I managed to create a full-proof guide to pass the McKinsey Solve game.
McKinsey PSG Simulation video included in the Guide
And thanks to that, this is what people are saying:

"This guide really helped me to pass the game! Francesco's guide gave me a real step-by step plan which is both intuitive and fast." Boris - August 10

"I cannot imagine doing the PSG without reading this guide. It has everything you need to pass. the HR just emailed me that I passed and will go to interview rounds. Thanks Francesco!" Luki - October 15

"Francesco has done a tremendous amount of work and I must admit that it is much more than I could expect from a Guide on solving the Imbellus Game. It is waaaay more!" Aleksandra - December 6

"Thank you, Francesco! I found the written guide and video's extremely helpful in my preparation for the assessment at the Sydney - McKinsey Digital office. Highly recommend. ^_^" Travis - August 12

"This guide is a must-have for Imbellus, since you only get one shot at it! This is by far the best resource out there for Imbellus, it's 100% worth the price!" Alen - April 6
And if you are curious if these are really replicable stories: check here some of the hundreds of McKinsey Solve Game tests I helped to pass in just a few months!
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So… What Is This Perfect Guide
(and how can it help you get your dream mckinsey offer).
Over the past 2 years, I have spent hundreds of hours finding information on the McKinsey Imbellus Game and created a guide that:
- Allows you to watch real video examples of the most common games
- Explains step-by-step how to solve the McKinsey problem solving test and crack all the possible game variations (and not just the popular ones)
- Answers all your questions and breaks down all the myths and misconceptions on the McKinsey game assessment
After helping hundreds of candidates, I am finally ready to offer you the ultimate McKinsey Solve game practice program to achieve all of this and more – the McKinsey Imbellus Solve Combo guide.
The techniques and methods you will learn in this course have now helped hundreds of people to ace the McKinsey game test and land a McKinsey offer.
In the last few months only, I helped
More Than 1000 Candidates to Crack the McKinsey Solve Game
All by applying what they learnt in my course! And in case you are wondering, this course has
Received More than 200 5-Star Reviews on Independent Platforms

And now I want to HELP YOU to master the game, so you can get an offer from McKinsey as wel l!
Master the Skills to Pass The McKinsey Test Game

When you enroll in the McKinsey Combo… Here Is What We Will Cover In Details
Introduction.
Would you like to understand what the game is really about? That’s exactly how we will start in order to unlock all the PSG secrets of the 70-minute digital assessment with tens of McKinsey Solve tips.
You will learn the structure of the McKinsey Assessment and the basic flow of the Ecosystem Management and Plant Defense games, plus the real alternatives to these games.
- Video 1: Welcome [2m14s]
After this, we will move to…

Ecosystem Game - The Basics
The first game in the McKinsey Solve test is the Ecosystem Game. But what are the key rules for this game? That’s what we will explore next.
I created a 3-video series that explains every single part of the Ecosystem Management in the McKinsey Digital Assessment in a real video simulation, including the trick to start your chain during the untimed tutorial that 99% of the candidates miss .
- Video 2: The Structure of the Imbellus [4m29s]
- Video 3: Starting the Tutorial [9m16s]
- Video 4: The Rules of the Game [11m30s]
Next, we will move to…

Ecosystem Game - Building the Chain
McKinsey allows for 35 minutes to complete the first game. Would you like to learn how to solve the McKinsey game and create a chain in just 16 minutes ? That’s what we are going to cover next.
We will see how to build the chain with the McKinsey Game Excel template included with the guide , so that you can complete the first game with ease and save time for the following one.
And with the last update, now you can also check in one click and less than 30 seconds if your chain is sustainable , saving a ton of time.
- Video 5: Starting the Food Chain [6m54s]
- Video 6: Finding the Animals [8m0s]
- Video 7: Completing the Chain [13m45s]
- Video 8: The Automated Excel [18m49s]
- Video 9: The Ecosystem Chain Check [7m36s]
And moving on, we will see…
PART 4 (NEW!):
Redrock study - the basics.
Stating from March 2023, McKinsey added the Redrock Study as the 2nd game in the McKinsey Solve game with 4 total parts, one of which has never been used before . How can you prepare for this new game and, in particular, the new section where most candidates fail?
Don’t worry, we have you covered. I created for you a complete intro guide to the Redrock, explaining each of the 4 sections in great detail. You won’t have to worry about any surprise after watching the videos.
- Video 10: Redrock - Introduction [3m28s]
- Video 11: The 4 Phases of the Game [3m37s]
And then, we will move to…
PART 5 (NEW!):
Redrock study - the details.
Once you understood the basic structure of the Redrock, we will drill down on every single part of the new game. Most candidates spend most of the time in the initial 3 parts, and don’t have enough time for the last section, the newly added one, consisting of 10 different mini-cases.
But you don’t need to be one of those candidates! You will find out how to complete the research part in just 4 minutes , the exact time to dedicate to each section, the most common math question asked in the new 10-case part and much more.
- Video 12: Research Phase - Key Components [3m28s]
- Video 13: Research Phase - Info to Collect [6m18s]
- Video 14: The Analysis Phase [5m06s]
- Video 15: The Report Phase [2m40s]
- Video 16: The 10 Cases [3m40s]
- Video 17: Final Tips [2m04s]
And next, we will move to…
Plant Defense - The Basics
In the past, the usual second game in the McKinsey test was almost always Plant Defense (Redrock is now the most common). What are the key rules of the game for it? That’s what we will check next.
Through a series of 3 videos, we will cover every rule of the Plant Defense game in the McKinsey assessment with a real video simulation. You will learn all about the 4 types of defenders and 3 types of barriers , and you discover exactly how to use them to solve McKinsey’s game.
- Video 18: Starting the Tutorial [8m6s]
- Video 19: Terrains, Defenders, Invaders [6m22s]
- Video 20: How to Win the Plant Defense Game [11m15s]
And we are not done yet, because…
Plant defense - Map Simulations
McKinsey asks to resist at least 15 turns in the Plant Defense game. Would you like to learn how to resist 25+ instead? That’s great, because you will watch how in the following videos 😉
We will see 2 separate McKinsey Solve simulation maps of the Plant Defense game to boost your McKinsey game practice and also cover the possible variations of the game that may occur.
- Video 21: Simulation #1 - Tutorial [5m51s]
- Video 22: Simulation #2 - Real Map [19m19s]
- Video 23: Plant Defense Variations [3m53s]
Ready for the next steps?
We will end by discussing the actions you can take to further turbocharge your preparation before the big day so that you can be sure you are ready for the McKinsey problem solving test !
- Video 24: Conclusion [1m54s]
And if you really want to go extra deeper in the game, you can also play the game now 😉 Because you can also benefit from…
ADD ON ($47) - NEW!
Mckinsey solve ecosystem simulation.
The videos are great..but what if you could actually PLAY the Ecosystem game in advance (for most candidates, the most challenging part of the test)?
Don’t worry, we have you covered for that as well 😉 I created for you the perfect simulation for the Ecosystem Game. You will be able to test your skills, with not 1, not 2, but 3 different ecosystems ! And you can play the scenarios unlimited time .
I guarantee that you won’t have any surprise in the game after this (and when I say I guarantee, I mean it – see below!). With the Ecosystem Game Simulation you will benefit from:
- 3 different scenarios , including both Coral Reef and Mountain Ridge
- Unlimited play for each game scenario
- Above-average difficulty for the scenarios, with all the possible traps of the game, so that you won't have any surprise
And even if we are done with the videos and all the PSG secrets, we are not done yet with the Combo. There are a few other McKinsey solve game tips ready for you 😉
Discover The Best Method To Pass The McKinsey PSG

With the McKinsey Solve Combo Guide you will also gain access to my supporting materials for FREE!
With the Combo, you will receive for FREE the following course material:
BONUS #1: McKinsey Imbellus Solve Game Secrets Guide (152 pages)

TOTAL VALUE: $59
Bonus #2: automated chain check algorithm.

Would you like to know in advance if your chain is going to be sustainable?
I created for you the ultimate algorithm to find out if the Ecosystem will work given your selection in the McKinsey assessment game. In just 30 seconds you will know if the species you selected can actually create a sustainable chain.
Available EXCLUSIVELY with the McKinsey Imbellus Solve Combo video simulation.
TOTAL VALUE: $39
Bonus #3: automated mckinsey solve game excel template.

Would you like to automatically create your chain without having to use any other tool?
I developed for you an automated McKinsey Game Excel template that can help you to complete the Ecosystem Food Chain in as little as 16 minutes. This is the ideal complement to your McKinsey game practice.
TOTAL VALUE: $29
Bonus #4: ultimate psg secrets industry cheat sheet (62 pages).

Do you want to get the essential knowledge of the main sectors in consulting?
I created for you a 62-page guide that covers the essentials of 17 different industries, including key activities, sectors and segments, company examples, and key implications for cases. This McKinsey Imbellus cheat sheet is the ideal companion for your interviews after studying with the McKinsey PSG simulation.
Learn All The PSG Secrets And Get A McKinsey Offer
The McKinsey Solve Combo has a value of $187, not including the material above, which I normally price at $156:

Watch how to create a chain in 16 minutes and resist 25+ turns in the Plant Defense game

Crack every scenario of the McKinsey Problem Solving Game

Find out in 30 seconds if you can build a sustainable chain for the Ecosystem Game

Build a Chain in the Ecosystem game in just 16 minutes

Get the essential knowledge of the main sectors in consulting
For a Grand Total of $343
I am offering for a limited time the combo with lifetime access at the discounted rate of $343 $99 , with all the material for free, with a 71 % discount, please note that i will change this offer soon . so if you want to secure the current rate book it now before the price goes up.
Oh, and one more thing…
“You’ve Gotta Be Crazy” Guarantee
In case you purchase the McKinsey Imbellus Solve Combo via this site – the PSGSecrets.com website (this guarantee is NOT available anywhere else):
If you don’t pass the test within 60 days and you tell me the Combo was not worth it, I will refund 100% of it .
That’s right. Just send me the email with the rejection from the test within two months from the purchase and I will give your money back within 12 hours.
If you are thinking “How the hell can you offer this crazy guarantee?” , it is simple.
The Combo works.
I know you will pass the test if you follow my tips.
That’s why I can offer this , and all the other course creators that created guides for the game are not offering it.
So you don’t even need to decide right now. Take the program and decide after it, based on the outcome.
Because yes, you will pay $99. But you can’t lose .
- Best case : you pass the McKinsey Solve game.
- Worst case : you tell me you didn't pass the McKinsey game and that the Combo was not worth it and I will refund 100% of it. And yes, you can even keep all the bonuses.
Both options are risk-free. You have NOTHING to lose and EVERYTHING to gain by getting the McKinsey Solve Combo Guide.
The only thing guaranteed not to help you is NOT taking the McKinsey Imbellus Solve Combo today.
Crack the McKinsey Game Assessment and Land your Dream Job At McKinsey

You will find:
- Many guides that claim they can help you to crack the McKinsey test game
- Very few guides that can show unbiased third-party reviews of candidates
- Even fewer that can show a real success rate of the candidates who followed their McKinsey game tips
- And none (but mine) that will give you a 100% money-back guarantee , as a real proof that the program works
With the McKinsey Solve Combo, you don’t just get “a course”.
You get the knowledge I developed in hundreds of hours of research on the McKinsey online test, all condensed in one single course, the proof that it works and the guarantee that I will help you until you pass the Solve game.
And that’s what you are investing in.
Any question? Drop me a message in the chat, I will reply within 12 hours.
I look forward to helping you get into McKinsey!

What’s more, if you don’t pass the test within 60 days and you tell me the course was not worth it, I will refund 100% of it.
So, c lick the button below and join the hundreds of candidates that I helped to get into McKinsey . I look forward to helping you land your dream offer!
Unlock The Best Way To Pass The McKinsey Game

Frequently Asked Questions
Right now, 89% . I know it because I refund everyone who doesn’t pass .
You will make $100k+ with your McKinsey job in a few years. Most people don’t prepare and fail the McKinsey Assessment. With the McKinsey Solve Combo, you either pass the test or you get your money back thanks to our 60-day money-back guarantee. So it is completely risk-free.
Yes! We get feedback weekly on possible changes and usually update the course for any possible changes within 48 hours (and yes, we do include the Redrock as well now).
The reason we are so quick is that you automatically get a 100% money-back guarantee if you don’t pass. So we have all the interest for you to have the best possible material 😉
Let me give you 3 reasons in good consulting setting 😉 :
1. You will learn everything you need to know about the McKinsey Solve main games in just 2.5 hours
2. If you don’t pass, you get 100% money back thanks to our 60-day guarantee
3. Even in case of a full refund because you are rejected, you can still keep all the bonuses.
Just watch the simulation and you will learn everything you need about the main game in 2.5 hours . If you want to go deeper, I also offer a free 152-page pdf guide with everything you need to know on the game. This is the fastest way to learn about the Imbellus game, risk-free.
You will just need 2.5 hours to learn everything you need about the main McKinsey games via the videos. And this is risk-free – if you don’t pass the game, just forward me the test rejection email within 60 days from the purchase and you will get your money back.
We will see how to solve the Ecosystem, Redrock Study and Plant Defense games step-by-step, with actual replicas of all games. You will learn how to create a chain in 16 minutes instead of 35 in the Ecosystem game , how to master all the 4 Phases of the Redrock Study and how to resist 25+ turns instead of 15 in the maps of the Plant Defense game . I have currently a 89% passing rate with the course (I know because I refund everyone who doesn’t pass).
Besides that, the course includes the McKinsey Imbellus Solve Game Secrets Guide with all 6 games described in 152 pages (including the Redrock Study), the Automated Excel, the Automated Chain Check Algorithm and the Consulting Industry Cheat Sheet .
Yes! If you don’t pass the test and you tell me the Combo was not worth it, I will refund 100% of the course , just forward me the test rejection email within 60 days from the purchase. Please note that I can offer the guarantee only if you purchase the course on the psgsecrets website (this site) – I cannot provide it if you buy via other third-parties.
It is sufficient that you forward me the rejection email of the test within 60 days of the purchase, I will then refund 100% of the course.
No! This is a one-time payment and you will get lifetime access to the course and bonuses.
No! You will get lifetime access to the course and bonuses.
Yes! If you are thinking how is this possible, it is simple: the McKinsey Imbellus Solve Combo works, so I know you will pass the McKinsey game if you follow what shown there.
Yes. We have recently added 8 new videos explaining all the 4 new parts of the Redrock Study (including the new part with 10 cases).
No . You won’t get the same bonuses and guarantees. Please note that I cannot provide the 100% money-back guarantee if you purchase the product on any website different from psgsecrets.com.
Please drop me a message in the chat, I will reply within 12 hours .

PSG Secrets
The McKinsey Imbellus Solve Combo Guide offered on PSG Secrets (henceforth referred to as “Combo”) is a product independently researched and developed by CaseMaster Pte. Ltd. (henceforth referred to as “CaseMaster”). All of the Combo, including but not limited to, comments, guidance, experience, numbers, texts, algorithms, images, database are created independently by CaseMaster. CaseMaster is not part of, or associated to, McKinsey & Company and/or Roblox Inc. and/or Imbellus Inc. (henceforth referred to as “McKinsey and Test Partners”), nor provides any product and/or service, including the McKinsey Imbellus Solve Combo Guide, on behalf of McKinsey and Test Partners. This website is not part of any of the McKinsey and Test Partners websites or McKinsey and Test Partners. Additionally, this site is not endorsed by McKinsey and Test Partners in any way. McKinsey, Roblox and Imbellus are trademarks of McKinsey & Company, Roblox Inc. and Imbellus Inc. respectively. The purpose of the Combo is to provide skill training and guidance for CaseMaster’s customers. Any similarity between the Combo and any other test is coincidental. It neither represents nor replaces any actual tests provided by any third party, including, but not limited to, McKinsey and Test Partners, and has merely an educational value.
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A Detailed Guide To The McKinsey Problem Solving Game
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Table of contents
Many candidates applying to McKinsey are focused on sharpening their resumes and practicing case interviews.
However, they forget that there’s another stage of the recruitment process: The McKinsey Problem Solving Game. And because they are unprepared, they don’t make it through to the case interview stage.
So in this article, we will teach you how to ace the McKinsey Problem Solving Game and progress through the recruitment process.
What is the McKinsey Problem Solving Game?
The McKinsey Problem Solving Game (also known as the McKinsey Digital Assessment, McKinsey Solve or the McKinsey Imbellus Test) is a gamified aptitude test that all candidates must take as part of the McKinsey recruitment process. It plays a similar role to the BCG Pymetrics Test .
The game has replaced paper-based aptitude tests and tests your cognitive and higher-order thinking skills in a simulated environment.

Who needs to take it?
The McKinsey Problem Solving Test is a compulsory stage of the recruitment process in most geographies.
Why does McKinsey use it?
McKinsey’s previous aptitude tests were more traditional question-answer style tests.
Because of this, candidates were able to prepare for the tests. They would gather advice from candidates who had already completed the test and practice similar standardized aptitude tests.
The issue for McKinsey was that they couldn’t differentiate a candidate’s preparation from their underlying skill.
What does the game evaluate?
The McKinsey Problem Solving Game evaluates the following abilities:
- Critical thinking: The ability to quickly and accurately synthesize and understand complex information.
- Decision-making: The ability to select the best course of action based on sometimes insufficient information.
- Metacognition: The ability to step back, evaluate the way you’re approaching the problem, and improve your approach.
- Situational awareness: The ability to understand and respond to complex and ever-changing environments.
- Systems thinking: The ability to figure out the underlying patterns and cause-effect relationships of an environment.

Format of the game
The McKinsey Problem Solving Game is designed to look and feel much like a video game.
You will be presented with a number of scenarios that are designed to test the five abilities we discussed earlier. The game will take 70 minutes in total.
However, not only are the scenarios chosen at random, the rules within each scenario are randomized. This makes each experience unique and means that there’s little benefit to knowing somebody else’s approach.
Each scenario begins with a tutorial to help you familiarise yourself with the game. There is no time limit, so you should take your time to understand the scenario mechanics.
You will be presented 2-3 scenarios from the following:
- Ecosystem management : You are required to build a sustainable ecosystem of species. There are animals and plants to be placed in the environment based on various factors like the food chain, terrain, nutrients, etc. You have to pick species and locations in such a way that it leads to the most suitable ecosystem.
- Plant defense: You are required to protect your plantation from predators. This is a turn-based game and the intensity of attacks increases with every turn. You must select and place defenders in such a way as to protect your plantation from predators.
- Disaster management: You are required to respond to disasters that affect your ecosystem. You must identify the type of disaster and location, and migrate your animals to a safer location.
- Disease management: You are required to respond to a disease that is spreading amongst your animals. You must identify the type of disease and determine the most appropriate treatment plan.
Tips for acing the game
Although it is difficult to directly prepare for the McKinsey Problem Solving Game, there are some things you can do to increase your chance of success:
- Familiarize yourself with the gamified environment. Watch preview videos that are available online and test out similar games.
- Review the scenario introduction thoroughly. Don’t rush through, as you can take as much time as you need.
- Ensure that you have at least 90 minutes of time that is completely free of distractions. The test takes 70 minutes but you’ll use the extra time to familiarize yourself with everything.
- Learn to be comfortable making decisions with limited information. The game is designed to test your ability to make quick, judgment calls with insufficient data.
How important is the game?
The McKinsey Problem Solving Game is an important part of the recruitment process. However, McKinsey doesn’t make a decision solely from your game results.
Your results will be considered together with the rest of your application, and a decision will be made as to whether you progress to the case interview stage.
Fortunately, McKinsey will provide you with your score and which quartile of benchmarked scores you fall into (e.g. top 25%, 25-50%, etc).

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- Healthcare Investment Banking
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- Investment Banking vs Hedge Fund vs Private Equity
- Investment Banking Salary
- Top Investment Banking Exit Opportunities
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- How to Prepare for Hirevue Interview?
- Superday of Investment Banking
- Why Investment Banking
- Goldman Sachs Internship
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- Private Equity Salary
- Private Equity Associate & Private Equity Analyst
- Private Equity Internship: The Complete Guide
- Private Equity vs Venture Capital
- Distressed Private Equity
- Real Estate Private Equity
- Private Equity Interview Questions
- Growth Equity
- Private Equity Associate: The Complete Guide
- Hedge Fund Salaries
- Hedge Fund Interview Question
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- Life of a Hedge Fund Analyst
- The Hedge Fund Career Path
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McKinsey Problem-Solving Game: How to Prepare and Ace the Game (Update 2021)
Replacing paper-based PST examination, McKinsey is deploying the game-based assessment that leverages artificial intelligence and algorithms to score candidates. McKinsey argues that the game, unavailable anywhere else online, strips biases and inherent advantages from the testing process. Candidates are no longer able to practice in advance as they did with the PST. Regardless of their backgrounds, candidates are now equal.
1. What is McKinsey Problem-Solving Game?
The McKinsey Problem-Solving Game , also called McKinsey Digital Assessment or Imbellus Game, is a gamified assessment developed by the Imbellus company. The digital assessment translates the real world of consulting into a set of games that allow McKinsey to score how candidates think and approach problems. According to McKinsey, there is no preparation and business background needed for the game.
After passing the resume screening round, McKinsey will send you the information with a link you need to get started. The process is now more flexible, allowing you to take the test either from home or at the test center set up by McKinsey. You can choose to take the assessment on your laptop, PC, or Mac. Once you are in the system, a technical check will inform whether your devices meet specific requirements. Then you will be given instructions about the assessment, including a video tutorial before entering each game.
1.1 Problem-Solving Game is now applicable to all positions McKinsey recruits
The PSGs are now applicable to all applicants applying for McKinsey. McKinsey has been rolling out the games to about 80% offices around the world. The rest will use the game in the next 1 to 2 years. In the past, some offices did not require candidates to join the test round if they have a good GMAT score and an MBA. But these are not advantages since the games are introduced. All applicants are now equal to one another.
1.2 There are no right or wrong answers for the Problem-Solving Game
McKinsey is looking at how you approach problems by playing a series of 2 out of 5 games, which will be customized to each candidate. In other words, they evaluate how you reach the solution rather than getting the right answer. The choice you make and the path you take in playing games will be collated to inform recruiters whether you are the best fit and most likely to succeed in consulting.
1.3. No business knowledge is tested nor will you require any experience in video gaming
Candidates will not be tested on business knowledge. Prior experience in video gaming, according to McKinsey’s talent acquisition team, is unnecessary either. In other words, any inherent advantages such as business and industry background will be removed.
They want to create equality between candidates no matter what their background is. In fact, while no testing on business is true, getting familiar with playing video games in a gamified environment might definitely give you an edge over candidates without practicing beforehand.
So does it contradict what McKinsey mentions?
No, we will get to this point and you will find out later in this article.
2. McKinsey Problem-Solving Game Format: How It Works?
2.1 it is a timed 60-minute assessment.
The time limit hovers around 60 – 80 minutes. Candidates sit the two games officially for 60 minutes, and the rest of 15 – 20 minutes is for tutorials and instructions. The time for each game varies from candidate to candidate, with around 35 – 40 minutes for the first game and 20 – 25 minutes for the second game.
All games in the digital assessment are brain teasers , which means candidates have to brainstorm exhaustively. As a result, 60 minutes can cause you to be somewhat wiped out. So the best advice, though sounding cliché, is to keep yourself relaxed and have a little snack by your side to remain energetic throughout the games.
The game can be taken on a candidate’s personal computer and anywhere they stay most focused and productive.
For tutorials, you can either skip this part or leverage this time to make preparations such as getting an overview and drawing up possible strategies for the games you will play.
Candidates CANNOT pause the games once entering the system.
2.2 Candidates will play 2 out of 5 games
McKinsey confirms that five games will be used for the assessments, including Ecosystem Building, Plant Defense, Disease Management, Disaster Management, and Migration Management. Ecosystem Building is the first game with two versions designed either in aquatic or terrestrial environments. The other four are used interchangeably for the second game.
In terms of the first challenge, candidates are placed into either a mountain ridge or a coral reef randomly. The overarching goal is to design a sustainable ecosystem with a chain of animals.
The second game, Plant Defense Game, largely resembles a tower-defense game where you place defensive objects to prevent invaders from approaching your base.
Nevertheless, the Plant Defense Game is just what most candidates will encounter in regard to the second game. A small percentage of candidates can take one of the “less frequent” following games as follows:
- Disaster Management involves identifying the nature of natural disasters such as hurricanes or wildfires and relocating the animals to the best area possible to minimize or to prevent the devastation caused by the disasters.
- Disease Management requires candidates to identify the infectious disease and the patterns of the disease , and given disease factors, to figure out what animals can be impacted.
- Migration Management involves migrating a group of animals to another destination on the best route out of many other “best routes” while sustaining the most amount of resources and animals.
While Disaster Management and Disease Management are becoming extremely rare (few reports are collected and according to people familiar with the games, they are still beta versions without any official results being produced) , Migration Management appears to be the second most frequent game besides Plant Defense. It means that you are much more likely to encounter Migration Management than the other two .
2.3 Candidates are evaluated on five main skills
Candidates will be assessed based on five main skills including critical thinking, decision-making, meta-recognition, situational awareness, and adaptability. Excelling at these five qualities foreshadows a great consultant a candidate might become.
The technology will only manage to focus on non-verbal cues. Results interpreted from the games essentially only assess candidates to a certain extent. A more complete version of consulting portraits is reflected best in case interviews.
It is difficult to tell what dimensions have the most weight. Those all five are minimal fundamental skills a consultant must possess.
3. Mini-Game 1: Ecosystem Building
3.1 what is your task.
Your task is to build a sustainable habitat for 8 species across the list of 40 species. Randomly, you might fall into one of two environments: a coral reef or a mountain ridge.
Following are what is worth noting before delving into the game:
- Create a food chain of 8 species with predators and preys , you have the right to choose and change the animals until they fit the food chain. According to feedback from real test takers, it is impossible to form a perfect food chain , meaning that the chain you form might carry unsolved conflicts . So you don’t need to worry too much. The more animals survive, the better.
- Summarize a plethora of information. You might be astounded by the information offered by the game, with most of them being unusable and redundant. So practicing in advance might give you a chance to think of strategies to practice taking notes and summing up such a huge load of information.
- Make the food chain not only continuous but also compatible with the terrain so animals can survive with one another and complete their own missions.
3.2 An overview of the two habitats you are tasked to resolve
Here’s are commons and differences between the two locations:

Figure 1: Mountain Ridge

Figure 2: Coral Reef
3.3 Step-by-step guide to playing the Ecosystem Building Game
Each animal has its own specifications, this part only concerns the “CALORIES NEEDED” and “CALORIES PROVIDED” of each one.
- Calories needed: a level of calories a creature requires to survive.
- Calories provided: a level of calories that a creature can provide to another creature if consumed.
Here come the eating rules:
- The creature (called A1 for the sake of simplicity) with the higher calories provided eats first.
- A1 will consume its prey, and it picks the prey with the highest calories provided (No consumption happens if A1 is a producer)
- If there are two top prey creatures having the same calories provided, A1 will eat 1/2 of calories needed from each prey creature.
- A1 will then eat the prey with the second-highest calories provided if the calories needed starts to reduce. The prey which has been consumed by A1 will become extinct and out of the food chain permanently. In this situation, your food chain loses one animal.
- The cycles are the same with the next creature below the A1 in the food chain.
- At the end of the process, all species in the food chain have new calories provided and calories needed. A species survives if its calories needed is equal to 0 and its calories provided is higher than 0.
Now that you’ve learned about the eating rule, here is the recommended step-by-step guide to playing the game:
Select the location
- Choose a specific location using a scratch paper to list the terrain specifications.
- There will be the same terrain specifications across all species and changing terrain specifications. Skim through all the data to identify this point.
Build the food chain
- Pick the apex animal with the lowest calories needed and put it on top of the food chain.
- Use a scratch paper to list the food sources of the top predators, An ideal food chain includes 4 levels, with a total of 8 species.
- Always prioritize species with high calories provided and low calories needed.
- If your food chain is not fulfilled with 8 species, look again to find gaps and add predators or plant-eating animals to the chain.
- You are highly recommended to draft the food chain on a paper because you’ll need to do some math calculations
Check and adjust to make all the animals fit the chain
- Check if the animals meet the requirements of each location.
- An ideal food chain should be continuous.
- Check if each species in the food chain is supplied with enough calories and not becoming extinct by being eaten because as said, the more animals survive, the better.
- Adjust the food chain accordingly if there are any unusually things happening in the food chain
4. Mini-Game 2: Plant-Defense
4.1 what is your task.
In the second game, you act as a plant protector from invader species trying to threaten a specific area of land (one square on the map – usually the brightest one). Your task is to arrange a set number of obstacles and predators to prevent those creatures from destroying the specific land.
You have to make judgments based on limited information to protect the particular land as long as possible. To do this, you’ll need to make a prediction of when and how the invaders would attack to protect the land.
McKinsey says that the work of consultants can change a lot and you are expected to adjust quickly and understand a client’s problem given limited background resources and information. The game is launched to measure this skill.

Figure 3: Plant Defense game
4.2 What do you need to know about the game?
4.3 how to beat the plant defense.
The objective of the game is to protect the particular land as long as possible, of course, the most optimally. Since it quite resembles a tower-defense game, tactics used in the Tower-defense game are essentially applicable to the Plant Defense game of McKinsey.
You won’t be able to change the objects once placed after a number of turns, and invaders appear from all directions so just paying attention to the appearance of invaders can’t help you that much in protecting your base land. Instead, plan for future invaders and predict, though hardly 100% precisely, where they could come from.
Strategy #1: Place as many layers as possible
Since invaders can come from anywhere from the border of the map, creating a round defense is necessary. You’ll need 8 resources to protect the particular land right away. 8 resources correspond to 8 cells around the land. Let’s see the picture below for clarity.

Figure 4: Plant Defense game
With this tactic, the most powerful resources will be prioritized to be put closest to the land, while the less powerful but wider-range ones cover the outer rings.
Strategy #2: Have a big picture mindset
Don’t just focus on specific starting points of invaders, they can come out from anywhere and at any time. You are expected to anticipate their appearance, possible trajectories, and arrange your limited resources with the only aim of keeping the particular land alive as long as possible.
There will be several types of invaders. Getting accustomed to them might take a few turns to test out what types of resources work best for different types of invaders.
5. Mini-Game 3: Disaster Management
Disaster Management, for the sake of simplicity, requires candidates to identify the natural disasters in an ecosystem and to relocate the animals to another area aimed at maximizing survivability (or minimizing the devastation caused by disasters).
This mini-game is an alternative to a plant defense game. Unlike the plant defense game, you will be allowed to play it once because it doesn’t include multiple maps.
6. Mini-Game 4: Disease Management
In the Disease Management game, you are tasked to identify the disease and make a prediction of what animals can be impacted. Given disease characteristics, select a treatment to optimize for the animal’s survival.
The goal is explanatory. But it’s not as easy as it seems. You have to deal with a large volume of information and then bring out a treatment plan. Consultants are expected to work out a large volume of information quickly and precisely to mitigate the most risks. And this simulation mimics that setting.
7. Mini-Game 5: Migration Management
The Migration Management game requires candidates to migrate a group of 50 animals to another destination. What makes the game challenging is that there will be many routes, and you have to identify the best route to move the animals while sustaining the most animals and resources.
There are 15 stages and each stage has 3 – 5 turns from start to finish. In each stage, candidates can collect 3 additional animals or resources at certain points, and choose to multiply (1x, 2x, and 3x) some of their resources.
If not playing the Plant Defense game, there is a higher probability that you will encounter this game than the mini-game 3 and 4.
8. Tips to Ace The McKinsey Problem Solving Game
Tip 1: read the preparation materials and understand the objective of each task.
Not reading the preparation materials sent by McKinsey before the game is one of the biggest mistakes candidates can make. You’re not going to fail just because of not reading, but it will eat up an extra 10 minutes of your time. If you still don’t understand the objective of each game, scroll up to read it through again. Each game, you’ll be tasked with different goals and have to approach it differently. Each game has its own rules and requirements, too.
Tip 2: Don’t get overwhelmed by a large volume of information
The games reflect the complexity of the type of work that consultants must do. Information in the game can get you overwhelmed the first time. Note that there will be too much information but only a limited amount of information can be used. Learning how to ignore inessential information is one of the skills of a future consultant. So, keep calm and always go with a paper to draft anything that comes up in your mind. This way can help you arrange your ideas and tactics to ace each game. Also, you will need to do some math calculations.
Tip 3: Don’t replicate other candidates’ solutions
Other candidates’ solutions will not be applicable to your scenario. The game itself can produce a lot of scenarios, each of which is unique to every candidate to prevent candidates from cheating the game. If you use the same tactics and food chain of former successful candidates, mostly it won’t match your scenario and you are out of the race.
Tip 4: Learn to compromise
There will be shortcomings in even the best solutions. So don’t worry too much if your plan doesn’t go as expected. The most important thing here is to focus on the time limit and submit your outcome before the time is up. Paying attention to achieve the perfect outcome only wastes your time and resources as a consequence. Especially the Plant Defense game, no matter how you place obstacles to prevent invaders, your particular land will be invaded sooner or later. If you are satisfied with your solution, submit it.

Tip 5: Find a tranquil place to take the test
Sitting in a place where you would be easily distracted will prevent you from concentrating 100% to come up with the best solutions. If you take the test in the test location set up by McKinsey, it won’t be a problem. If you take the test from your home, remember to remind your mates or family members to keep silent while you’re playing the game. Concentration is very important.
Tip 6: Check your computer and internet before playing the game
You are given a time period to play the game and must complete it before the deadline set up by the firm. So choose to play when you are most confident and the internet connection is fast and stable. If you lost connection in the middle of the game, contact the technical team (contacts will be provided in the email that McKinsey sends). If lucky, they will arrange your test time to another time, or help you save your data until your internet is reconnected.
9. Practice with Several Similar Games
Some of the game genres that have many similarities with the McKinsey PSG are City-building games, Tower Defense games, and Grand strategy and 4X games. City-building games are very similar to the Ecosystem Building mini-game while the Tower Defense can be used to practice the Plant Defense game.
9.1 City-building games
This genre includes SimCity series, Caesar series (Zeus and Poseidon, Caesar II, and Emperor ROTK), Anno series (Anno 1404, Anno 2070, etc.), and Cities Skylines. You can leverage these games to practice the Ecosystem Building game. The most significant difference between these games and the PSG is that these games are continuous and you have the right to correct the mistakes if you have – while in the PSG you have limited time and mostly need to complete the system from the start. But it is still a perfect type of game for practicing the Ecosystem Building game due to the similar logic.

Figure 5: Cities Skylines
9.2 Tower defense games
Kingdom Rush series and Plants vs Zombies series largely resemble the Plant Defense game, with a difference that both games allow you to correct your mistake multiple times before you lose while the Plant Defense game does not. The paths of invaders in both games are fixed and predictable, making it less challenging compared with the Plant Defense game, where the paths of invaders change according to your actions.

Figure 6: Kingdom Rush 2
9.3 Grand strategy and 4X games
Three series include Civilization series, Europa Universalis series and Crusader Kings series. These games are good practice for the PSG since the logics of Grand strategy and 4X games are quite similar.

Figure 7: Civilization VI
10. PSG Simulation Developed by MConsultingPrep
McKinsey says that no business knowledge is tested and no additional preparation is required since the games are essentially not available anywhere else in the world. However, in order to help candidates get accustomed to the gamification experience and learn more deeply about the objectives as well as complicated rules of the games, MConsultingPrep (MCP) releases a PSG Simulation (can be seen as a mock test for you to practice in advance).
What the PSG Simulation offers:
- 50-page in-depth strategy guide
- Template spreadsheets for the Ecosystem Building game
- A number of practice scenarios produced by the algorithms, with a 95% similarity to the real PSG
PSG Simulation Developed by MConsultingPrep

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Table of Contents
- 1. Problem-Solving Game
- 2. How it Works?
- 3. Mini Game 1
- 4. Mini Game 2
- 5. Mini Game 3
- 6. Mini Game 4
- 7. Mini Game 5
- 8. Tips to Ace the Game
- 9. Similar Games to Practice
- 10. PSG Simulation

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McKinsey Solve Game: Newest Updates & Guide (May 2023)
Check out the only, fully-simulated McKinsey Problem Solving Game (Solve) Simulation in the entire market. There is also a new, data-focused test called "Redrock Study Task" in 2023, being tested in various locations across the globe - and we've got that covered as well.
You can also bookmark this article - or our corresponding video on Youtube for a free, detailed guide on the McKinsey Problem Solving Game that you can come back any moment.
With that out of the way, let's continue to learn about the test, shall we?
What is McKinsey Problem Solving Game (a.k.a Solve)?
The mckinsey problem-solving game is a gamified test.
The McKinsey Problem-Solving Game (McKinsey PSG) is a gamified test designed by the assessment company Imbellus for the consulting firm McKinsey & Company. The new game/test has entered trial since 2017 and has been rolling out extensively in 2020. By January 2021, the Problem-Solving Game had replaced the paper-based PST in virtually every McKinsey office.
In the McKinsey recruitment process, the Problem-Solving Game sits between the resume screening and the case interviews , serving the same purpose as the paper-based tests – ruling out the “unfit” candidates to save time and resources during the expensive case interview phase. The test is mandatory for candidates applying in all practices: General, Operations & Implementation, Research & Analytics, Digital, etc.
Note: As this is a gamified test, in this article, the two terms “game” and “test” will be used interchangeably when referring to PSG.
McKinsey PSG Simulation (All-in-One)
The one and only existing platform to practice three mini-games of McKinsey Solve in a simulated setting
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The new gamified test is supposedly crack-proof
Now, why did McKinsey change the test format from a paper-based test to a game? Keith McNulty, McKinsey’s Global Director of People Analytics and Measurement, put it this way:
So essentially, McKinsey is trying to create a test/game that is impossible to game (ironic, isn’t it?).
But in fact it can be broken down into bite-size pieces
With field reports from hundreds of real test takers, we have gathered enough insights to break down the McKinsey Problem-Solving Game into bite-size pieces, which are fairly consistent across candidates. Using those insights, we can derive working overall approaches to the game.
In this article, we will cover:
- Technical details of the test : time limit, number of tasks and mini-games, assessment criteria
- Break-down of each mini-game : description, underlying logic, and recommended strategy
- Test-taking tips to maximize your chances
- Similar games for practicing the McKinsey Problem Solving Game
It is important to keep in mind that since neither Imbellus nor McKinsey publicizes the exact details of the criteria/mechanisms used in-game, the insights in this article – reported by our correspondents – may not reflect 100% of the in-game elements.
What is the McKinsey Problem Solving Game like?
The McKinsey Problem-Solving Game or Digital Assessment has a time limit of 60-80 minutes . The candidate is asked to solve 2 out of 5 possible mini-games . Both the final results and the process are assessed , and if the candidate is found to possess similar skills and tendencies to a McKinsey consultant, they are offered an interview.
For a more detailed guide on the technical details of the game, please check out the McKinsey PSG Simulation (All-in-one) package.

Time limit is 71 minutes
As of April 2021, the reported time limit for the McKinsey PSG is exactly 71 minutes , with 35 minutes recommended for the first game, and 36 minutes for the second game. Time spent on tutorials is not counted towards the limit.
Ever since the start of the PSG, there have been variations in time limit reports, however, these tend to stay between 60-80 minutes . This variation depends on the length of each mini-game.
Actual time allocation depends entirely on the candidate’s decision – however since the first game is much more predictable, we recommend playing this quickly to allow more time for the second game. With a proper approach, the first game should take only 15-20 minutes , with time for a double-check taken into account.
Candidates should also make the most out of the tutorial time – try to guess the objective of the mini-game, and think of an overall approach before beginning a mini-game. You can also use that time to make necessary preparations, such as pen and paper, or maybe a light snack to keep yourself energized.
Each candidate has to solve 2 out of 5 mini-games
As of March 2023, 6 mini-games are confirmed for the McKinsey Problem-Solving Game. The two common mini-games are Ecosystem Building and Plant Defense , the less common ones are Redrock Study, Disease Management, Disaster Management, and Migration Management.
The first one is similar to city-building games – except with animals instead of buildings – and the second one is essentially a tower-defense game where you use defensive structure to protect the base from invaders.
Besides the Plant Defense game, four alternatives for the second mini-game are Redrock Study, Disaster Management, Disease Management, Migration Management.
- Redrock Study (the newest reported game on March 2023) is a blend between numerical/verbal tests and consulting work. The first part of the game asks you to pick relevant information from a pile of data, analyze them by answering 3 questions and fill in the blanks for a report. In the second part, candidates answer 10 stand-alone questions.
- Disaster Management involves identifying the natural disaster occurring in an ecosystem and moving the whole system to another location to minimize damage.
- Disease Management is about identifying an infectious disease, figuring out its rules of infection, and predicting its spread within an ecosystem.
- Migration Management is about directing a group of animals from one point to another such that it loses the least amount of resources and animals.
In most cases, these alternative mini-games are there for beta-testing purposes – the scores from those sessions are not likely to weigh heavily in the final decision.
For the latest insights on the game - Redrock Study, check out the section below or our designed simulation package for this mini-game.
As of March 2023, reports of the Disease, Disaster, and Migration mini-games have been come extremely rare, indicating that they have been phased out.
The next part will be about how candidates are assessed – if that’s not in your interest, you can skip straight to the mini-game and strategy guide using this link.
Every keystroke and mouse movement will be assessed
Each candidate will be assessed using both product scores (i.e. the final results) and process scores (i.e. how they get those results).
Product scores are determined by your level of success in achieving the objectives of the mini-games. While there is no 100% right answer, some solutions will be better than others. In the first mini-game, you will be given this information through a report screen. For the second mini-game, it would come from the number of turns you survived till the end.
- Mini-game 1: How many species survive?
- Mini-game 2: How many waves of invaders did you fend off?
Process scores, on the other hand, are dictated using data on your patterns during the whole problem-solving process – every keystroke, every click, and every mouse movement will be assessed.
The process and product scores are combined to form a profile of problem-solving skills and capabilities. And while there is no official statement from McKinsey about which candidates they select, it is likely that the more you resemble a high-performing consultant at McKinsey, the higher your chances will be.
Candidates are assessed on five core dimensions
Your problem-solving profile is drawn using the five following dimensions:
- Critical thinking : the ability to form a rational judgment from a set of facts
- Decision-making : the ability to select the best course of action among options
- Meta-cognition : the ability to use strategies to make learning information and solving problems easier (e.g., testing hypothesis, taking notes)
- Situational awareness : the ability to determine the relationships between different factors and to project the outcomes of a mini-game
- Systems thinking : the ability to understand cause & effect relationships involving several factors and feedback loops (e.g., anticipating several orders of consequences)
The good news is that all the skills assessed are generally not evaluated by themselves, which means training one skill will probably also drive up your assessment scores in others . This is absolutely crucial because you won’t have to go into every nitty-gritty task just to squeeze out some extra score.
Furthermore, while all capabilities must be presented for success, some metrics are considered to be more impactful than others. From this Imbellus research paper , we could deduce that Critical Thinking, Situational Awareness, and Systems Thinking are the fundamental skills that all successful candidates need to possess. Meanwhile, Decision-Making and Meta-Cognition skills mastery are the advanced skills that will transform candidates from good to great ones.

The test measure telemetry data to calculate the five dimensions
While it is hard to pinpoint exactly the telemetry data gathered since Imbellus does not fully disclose this information, one way of framing this is by each stage of the problem-solving process itself.
Based on our findings from real candidates, we believe the telemetry could be assorted into the following sets, each directly influencing the key activities during the stages from identifying the problem to delivering the next-step recommendation.
Problem Identification: your systematic thinking pattern
- Methodological vs. abstract
- Big-picture thinking vs. detail-oriented
- Example telemetry: prioritization and focus tendency, clicking and decision pattern
Quantitative analysis & data synthesis: the ability to translate data into insights
- Drawing relationship between data
- Filter out correlated or irrelevant information
- Example telemetry: data focus pattern, time spent on quantitative task
Hypothesis-crafting: bringing insights into actionable hypothesis
- Putting emphasis on a certain approach / methodology from insights
- Example telemetry: duration of the transition from analysis to decision-making, disrupted status quo period
Decision-making: coherence in actions and thinking
- Random selection or well-thought out decisions based on analysis
- Decisiveness in carrying out actions with the chosen tactics
- Reaction under growing time pressure – panic clicking vs. calm and focus
- Example telemetry: factors connecting each selection, time spent deciding between options
Next-step recommendation: learning and reflection
- Ability to adjust existing strategy and preference for tried-and-true method in presence of new data set or shifting conditions
- Progressive learning and reflection with failures and successes
- Example telemetry: number of clicks, scrolling speed, time spent on certain data blocks
Breaking down the test – Ecosystem-Building
Mini-game overview & description.
In the Ecosystem Building mini-game, you have to create an ecosystem with 8 species from a list of 40. There are three key objectives:
(1) the ecosystem must form a continuous food chain
(2) there must be a calorie surplus for every pair of predator and prey (that is, the prey’s production is higher than the predator’s consumption)
(3) the ecosystem must match the terrain specifications of the chosen location.
Here’s a detailed description of data and metrics in the mini-game, and how they relate to the objectives.
Objective 1: Terrain Match
There are two scenarios on which you must build the ecosystem: “the Reef” and “the Mountain”.
Each location in the Mountain world has the 8 following specifications: Elevation, Temperature, Wind Speed, Humidity, Cloud Height, Soil pH, Precipitation, Air Pressure.
Each location in the Reef has the 7 following specifications: Depth, Water Current, Water Clarity, Temperature, Salt Content, Dissolved Oxygen, Wind Speed.
Terrain specifications have very little correlation.
Each species also has a few required terrain specifications – if these terrain requirements are not met, the species will die out. These requirements are often not exact numbers, but ranges (e.g: Temperature: 20-30 C).
All 39 species are organized into 3 equal groups using their terrain specs – I call them “layers”. Species of the same layers have exactly the same terrain specs.
Objective 2: Food Chain Continuity
Each species has a few natural predators (Eaten By), and prey (Food Sources) – see below for exceptions.
The species are divided into producers (which are plants and corals, which consume no calories), and consumers. Consumers can be herbivores (plant-eating animal), carnivores (animal-eating animal), or omnivores (eats both plants and animals).
Producers always have the Food Sources as “sunlight” or other natural elements, i.e. they do not have prey. Some consumers are “apex animals”, meaning they do not have natural predators (can be recognized by empty the “Eaten By” specs). These have strategic implications in building the food chain.
Objective 3: Energy Balance
Each species has a “calorie needed” and a “calorie provided” figure. A species lives if its calorie needed is less than the sum calorie provided of the species it eats (so it has enough energy to survive) and its calories provided is higher than the sum calorie provided of the species that eat it (so it’s not eaten to extinction).
Two caveats apply here: a species often don't eat all of its prey and is not eaten by all of its predators. There are certain rules for priorities (see the “Feeding Overlap” issue) and more often than not, predators and prey will interact on a one-to-one basis.
In old versions of the game, each species will be placed on a group basis, with the number of individuals in each group ranging from 20 to 60. In these versions, calorie specs are “per individual”, so you have to perform the math to get the true consumption and production figures of the whole species.
New versions discarded this “per individual” feature, presenting the calorie specs for the whole species as one, but there is no guarantee the old feature won’t be re-introduced.
As of game-flow , the candidate is free to switch between choosing location and species during the mini-game. There is also a time bar on the top of the screen.
Old reports indicate that once you’ve submitted your proposed ecosystem, you would receive a scorecard in the end, showing how it actually plays out. Key measurements might include calories produced and consumed, and the number of species alive.
However, recent reports have indicated that results aren't displayed at the end. In either case, it is safe to assume that the underlying principles remain the same.
Cracking the mini-game
The biggest challenges in the Ecosystem Building mini-game are task prioritization and data processing – most test-takers report that they are overwhelmed by the amount of data given, and do not know how to approach the problem. However, the second problem can be mitigated by reading the rules very carefully, because McKinsey provides specific and detailed instructions in the tutorials.
To overcome both challenges at the same time, first, we need to know the “eating rules” (i.e. how species take turns to eat) and then we can develop a 3-step approach to meet those challenges.

EATING RULES AND FEEDING OVERLAP
In the McKinsey PSG Ecosystem mini-game, species take turns to eat and get eaten, in accordance to very specific and comprehensive rules:
1. The species with the highest Calories Provided in the food chain eats first.
2. It eats the species with the highest Calories Provided among its prey (if the eating species is a producer, you can assume it automatically bypass this step, as well as steps 3-5).
3. The eating species then “consumes” from the eaten species an amount of Calories Provided that is equal to its Calories Needed, which is at the same time substracted an amount equal to the Calories Provided taken from the eaten species.
4. If there are two “top prey” species with the same Calories Provided, the eating species will eat from each of them an amount equal to 1/2 of its Calories Needed.
5. If the Calories Needed hasn’t been reduced to 0 (i.e.: satisfied), even if the eating species has consumed all the Calories Provided of the first prey the eating species will move on to the next prey with the second-highest Calories Provided, and repeat the above steps; the prey that has been exhausted its Calories Provided will be removed permanently from the food chain and considered extinct.
6. After the first species have finished eating, the cycle repeats for the species with the second-highest Calories Provided, then the third-highest, etc. until every species has already eaten. Note: in every step where species are sorted using Calories Provided, it always uses the most recent figure (i.e. the one after consumption by a predator).
7. At the end of this process, all species should have new Calories Provided and Calories Needed, both smaller than the original figures. A species survive when its end-game Calorie Needed is equal to 0, and Calorie Provided is higher than 0.
Let’s take a look at an example – try applying the rules above before reading the explanation, and see if you get it right:

Now, here’s how this food chain is resolved:
- The three producers automatically have their Calories Needed satisfied and does not need to eat anything.
- The first species to eat is an animal – the Mouse. It eats equally from Grass and Mushroom, which have equal Calories Provided, an amount of 2,000 each. The Mouse’s Calories Needed reduces to 0, while the Calories Provided for Grass and Mushroom reduce to 3,000 each (Grass and Mushroom survive).
- The second species to eat is the Squirrel. It should have eaten Grass, but Grass’s new Calories Provided is only 3,000, so the Squirrel picks Nuts instead. Squirrel’s Calories Needed becomes 0, while Nuts’ Calories Needed becomes 500 (Nuts survive).
- The third species to eat is the Snake. It eats the Mouse, reducing its own Calories Needed to 0 while taking 2,000 from the 3,000 of the Mouse’s Calories Provided. (Mouse survives)
- The fourth species to eat is the Fox. It eats the Squirrel, reducing its own Calories Needed to 0 while taking 2,000 from the 2,500 of the Squirrel’s Calories Provided. (Squirrel survives)
- The last species to eat is the Tiger. It eats the Snake first, taking away all of the Snake’s 1,500 Calories Provided, then proceeds to take 500 from the Fox’s 1,200, so that its Calories Needed can be reduced to 0 (Snake becomes extinct, Fox survives)
- The Tiger is not eaten by any other animal (Tiger survives).

With these rules in mind, let us go through a 3-step process to building a food chain:
Step 1: Select the location:
- Use a spreadsheet or scratch paper to list the terrain specs and calories provided of the producers of the mini-game.
- Skim through the data to see which terrain specs remain the same across all species, and which ones change. Only changing terrain specs are relevant (there should be 2 of them), the rest are merely “noise” intended to cause information overload.
- Calculate the sum calories provided for the producers of each layer. The layer with the highest calories provided is likely to be the easiest to build the chain.
Step 2: Build the food chain:
- Look through the data to list the consumers with compatible terrain requirements in your spreadsheet.
- Pick the apex predator with the lowest calorie needed as the starting point of the food chain.
- Build the food chain top-down like an issue tree, by listing the food sources of the top predators. Continue drilling down until you reach the “base” level of corals and plants. Ideally the food chain should contain 3-4 levels, and 8 species.
- Alternatively, you can build the food chain in a bottom-up manner, by looking at the “Eaten By” specs of each species, until you reach the top predators. Our reports indicate that in real test conditions, this approach can be just as fast as the top-down one.
- During the whole process, try to prioritize species with high calories provided, and low calories needed. This should maximize the chance of calorie surplus in the food chain, and leave room for new additions should the first chain not meet the required 8 species.
- If you finish the chain short of the required 8 species, work bottom-up to find gaps (i.e unused surplus calories), and plug in those gaps with predators or plant-eating animals.
- The whole process should be done on a spreadsheet/scratch paper to facilitate calculations.
Step 3: Triple-check and adjust:
- Go back to the beginning of the process and check if every species of your food chain is compatible with the chosen location.
- Make sure the food chain is continuous – that is, the food sources listed fit with the description of each species.
- Check if each species in the food chain is supplied with enough calories and not eaten into extinction using the given eating rules.
- Adjust the food chain if any of the three checks are not met.
Breaking down the test – Plant-Defense
The second mini-game of the McKinsey Problem-Solving Game – Plant-Defense – is a turn-based tower-defense game. The candidate is charged with defending a plant at the center of a grid-based map from invading pests, using obstacles and predators, for as long as possible, until the defenses are overwhelmed and the plant is destroyed.

Here’s a detailed description of the gameplay:
- The visual map is divided by a square grid (size from 10×10 to 12×12), with natural obstacles (called Terrain, or Terrain Transformations) are scattered across the map.
- The game has a recommended time allocation of 12 minutes per stage – which makes 36 minutes in total.
- The game is divided into three maps, each with 2 phases – “planning phase” and “fast-forward phase”.
- The “planning phase” is divided into 3 waves of 5 turns each. Every 3-5 turns, a new stack of Invader appears at the border of the map and starts travelling towards the center base – you have lay out defensive plans to tackle them. The phase lasts until you eliminated all the Invaders / you survive at the end of the 15th turn / your plant is destroyed.
- The “fast-forward phase” comes after the 15th turn of the planning phase. All the remaining Invaders from the planning phase will continue attacking. Your defensive scheme remains unchanged, and unchangeable. Invaders will continuously spawn and attack until the base is destroyed.
- After you’ve finished the game, the number of turns your plant survived will be used as the basis for the product scores.
Game aspect 1: Resources
At the beginning of each wave, you are allowed to choose and place 5 resources – divided into Defenders (such as Coyote, Snake, Falcon etc. which kill the Invaders) and Terrains (comprised of Cliff, Forest, and Rocky, which slow down or block the invaders). Each will be assigned to one turn of the current wave.
After each turn, the Defender/Terrain of that turn will be activated and locked – meaning you cannot change or remove its placement. The rest can be altered to adapt with the circumstances. The only exception is the Cliff, which activates right after its placement.
Each Defender has a range/territory – once an invader steps into that range/territory, the Defender will damage them, reducing their population. The range vary between each Defender type – but in general the more powerful they are, the smaller their range is.
Each Terrain is effective towards different types of Invaders and in different ways, with some blocking the Invaders while others slowing them down.
Each Terrain and Defender will occupy one square. You cannot place Defender on top of an existing Defender, and if a Terrain is placed on top of an existing Terrain, it will replace the existing Terrain.
Defenders and Terrains form mutually compatible pairs which can exist on one same square.
Game aspect 2: Invaders
Invaders will appear from the map borders every 3-5 turns, in stacks of 100-200 population each, and move one step closer to your plant by each turn. The population of the stacks increase gradually.
Each Invader stack is accompanied by a path indicator – a long yellow arrow showing the direction it will take. The invader will always take this path unless blocked by Cliff.
Each Invader is countered by certain types of Terrain/Defender.

As the Plant Defense mini-game of the McKinsey Problem Solving Game is essentially a tower-defense game, the basic tactics of that game genre can be applied – namely inside-out building and kill-zones. However, as the mini-game locks you from changing placement after a number of turns, contingency planning is also necessary.
I’ll elaborate each of those tactics:
INSIDE-OUT, MULTI-LAYERED DEFENSE
In this tactic, you build multiple layers of defenders outwards from the base, assisted by terrain.
Place your resources close to the plant first. As the inner rings of the map are smaller in circumference, and paths usually converge as you advance towards the center, this helps you maximize the coverage of each resource around the plant early on.
In the example below, the “inside-out” approach only takes 8 resources to protect the plant from all directions, while the “outside in” approach takes 24. With this approach, place your most powerful resources closest to the plant, and expand with the less powerful, but longer-range ones.

BIG-PICTURE MINDSET
This isn’t so much of a “tactic”, but a reminder – after 15 turns, you won’t be able to change or place more resources, so try to identify the pattern of the invaders, and quickly adapt your strategy accordingly. It will take a few initial turns to experiment which works best for each type of invader.
Use your resources prudently, create an all-round protection for the plant – lopsided defenses (i.e heavy in one direction, but weak in others) won’t last long – and lasting long is the objective of this mini-game.
Alternative mini-games
Early reports also indicate 4 alternative mini-games as replacements for Plant Defense – called Disaster Management, Disease Management and Migration Management and Redrock Study (updated on March 2023) . With the limited information available, it seems these alternatives are rare, but it is best to know what their objectives are and how to deal with them.
Alternative 1: Redrock Study
The Redrock Study is the latest mini-game McKinsey rolled out in 2022 and recently, on March 2023, the test has come back in an updated version.
Its format is different from other mini-games. In Redrock Study, the candidate plays the role of a researcher with tasks following a research process. Within 25 minutes, candidates will be instructed step-by-step to move through three stages:
- Investigation stage: The candidate is presented with a research objective and an article featuring past data. The task is to collect the most relevant data points to their research journal.
- Analysis stage: In this stage, there are three calculation questions answering to the aforementioned research objective. The candidate will need to come up with the answers using the collected data and the virtual calculator provided. They can come back to the article if the data is inadequate.
- Report stage: Lastly, the candidate creates a summary and visualizes the data onto a suitable graph to reflect their post-analysis findings.
As of March 2023, Redrock Study is reported to be completed within 35 minutes, broken down into two phases. While Phase 1 remains the same format as the 2022 version, Phase 2 includes 10 standalone questions. Many candidates find the 10 questions heavy on qualitative skills and hard to solve within the allocated time limit.
Overall, the game tests a combined set of skills: chart reading, percentage calculations, and data interpretation. Mastering these skills individually by preparing for numerical reasoning tests can also familiarize you with question types.
MConsultingPrep has constructed a Simulation for Redrock Study , including an accompanied guidebook and mock cases to prepare you for the real Test. The Simulation is developed based on feedback from real test-takers in 2022. More content will be coming in the upcoming future (both free and paid) to reflect the 2023 addition of the 10 new "mini-case" questions.
Alternative 2: Disaster Management
In the Disaster Management mini-game of the Problem-Solving Game, the candidate is required to identify the type of natural disaster that has happened to an ecosystem, using limited given information and relocate that ecosystem to ensure/maximize its survivability.
With the two main objectives in mind, here’s how to deal with them:
- Identify the disaster: this is a problem-diagnosis situation – the most effective approach would be to draw an issue tree with each in-game disaster as a branch, skim through data in a bottom-up manner to form a hypothesis, then test that hypothesis by mining all possible data in game (such as wind speed, temperature, etc.)
- Relocate the ecosystem: this is a more complicated version of the location-selection step in the Ecosystem-Building mini-game, with the caveat that you will first have to rule out the locations with specs similar to the ongoing disaster. The rest can be done using a spreadsheet listing the terrain requirements of the species.
Like the Ecosystem Building mini-game, you will solve this mini-game only once, unlike the Plant Defense and the next Disease Management mini-games with multiple maps.
Alternative 3: Disease Management
In the Disease Management mini-game of the Problem-Solving Game, the candidate is required to identify the infection patterns of a disease within an ecosystem and predict the next individual to be infected.
The game gives you 3-5 factors for the species (increasing as the game progresses), including name, age, weight, and 3 snapshots of the disease spread (Time 1, Time 2, Time 3) to help you solve the problem.
There is one main objective here only: identify the rules of infection (the second is pretty much straightforward after you know the rules) – this is another problem-diagnosis situation. The issue tree for this mini-game should have specific factors as branches. Skim through the 3 snapshots to test each branch – once you’re sure which factor underlies and how it correlates with infection, simply choose the predicted individual.

Alternative 4: Migration Management
The Migration Management mini-game of the PSG is a turn-based puzzle game. The candidate is required to direct the migration of 50 animals. This group carries a certain amount of resources (such as water, food, etc.), often 4-5 resources, each with an amount of 10-30. Every turn, 5 animals die and 5 of each resource is consumed.
It takes 3-5 turns from start to finish for each stage Migration mini-game, and the candidates must place 15 stages in 37 minutes. The candidate must choose among different routes to drive the animals. In each stage, there are points where candidates can collect 3 additional animals or resources (1-3 for each type), and choose to multiply some of the collected resources (1x, 3x and 6x); the game tells the candidate in advance which resources/animals they will get at each point, but not the amount.
The objective is to help the animals arrive at the destination with minimal animal losses, and with specific amounts of resources.
With all of these limited insights in mind, here’s what I recommend for the strategy:
- Nearly every necessary detail is given in advance, so use a scratch paper to draw a table, with the columns being the resources/animals, and the rows being the routes. Quickly calculate the possible ending amount for each resources, assuming you get 2 at every collection point (good mental math will come in handy).
- Choose the route with the highest number of animals, and “just enough” resources to meet requirements.
Test-taking tips for McKinsey Problem-Solving Game
Besides the usual test-taking tips of “eat, sleep and rest properly before the test”, “tell your friends and family to avoid disturbing”, etc. there are five tips specifically applicable to the Problem-Solving Game I’ve compiled and derived from the reports of test takers:
Tip 1: Don’t think too much about criteria and telemetry measurements
You can’t know for sure which of your actions they are measuring, so don’t try so much to appear “good” before the software that it hurts your performance. One of our interviewers reported that he refrained from double-checking the species information in the Ecosystem Building mini-game for fear of appearing unsure and unplanned.
My advice is to train for yourself a methodical, analytic approach to every problem, so when you do come in for the test, you will naturally appear as such to the software. Once you’ve achieved that, you can forget about the measurements, and focus completely on problem-solving.
Tip 2: Don’t be erratic with in-game actions
While you don’t want to spend half your brain-power trying to “look good” to the software, do avoid erratic behaviors such as randomly selecting between the info panels, or swinging the mouse cursor around when brainstorming (yes, people do that – my Project Manager does the same thing when we do monthly planning for the website).
This kind of behavior might lead the software into thinking that you have unstable or unreliable qualities (again, we can never know for sure, but it’s best to try). One tip to minimize such “bad judgment” is to take your brainstorming outside of the game window, by using a paper, or a spreadsheet.
Tip 3: Always strive for a better solution (Ecosystem Building)
Some of the interviewed test-takers seem to be under a wrong impression that “the end results do not matter as much as the process” – however, for PSG, you need good end results too. This is especially true in the Ecosystem Building, where a “right” answer with no species dying can be easily found with the right strategy.
Consulting culture is highly result-oriented, and this game/test has product scores to reflect that. Having a methodical and analytical approach is not enough – it’s no use being as such if you cannot produce good results (or, “exceptional” results, according to MBB work standards).
Tip 4: Learn to compromise (Plant Defense)
The game is designed so that in many cases, there will be shortcomings in even the best solutions, and your base will never survive. So pay attention to the time limit, and once you’re confident with a “good enough” solution, submit it. Remember, the time limit is shared by all the mini-games and its constituent stages, so spending too much time on one will eat up the necessary time for the next.
Tip 5: Prepare your hardware and Internet properly before the test
While the McKinsey PSG does not require powerful hardware, the system requirements are indeed more demanding than the usual recruitment games or tests. A decent computer is highly-advised – the smoother the experience, the more you can focus on problem-solving.
On the other hand, a fast Internet connection is a must – in fact, the faster, the better. You don’t want to be disconnected in the middle of the test – so tell other users on your network to avoid using at the same time as the test, and go somewhere with a fast and stable connection if it’s not available at your home.
How to practice for McKinsey Problem-Solving Game
Hypothesis-driven problem-solving approach.
See this article: Issue Tree, MECE
You may have noticed a lot of the solutions for the mini-game involve an “issue tree” – the centerpiece of the hypothesis-driven problem-solving approach that real consultants use in real projects.
This problem-solving approach is a must for every candidate wishing to apply for consulting – so learn and try to master it by applying it into everyday problems and cases you read on business publications. Practicing case interviews also helps with PSG as well.
You can see the above articles for the important concepts of consulting problem-solving.
Mental math and fast reading skills
See this article: Consulting Math, Fast Reading
The McKinsey Problem-Solving Game – especially the 3 ecosystem-related mini-games – require good numerical and verbal aptitude to quickly absorb and analyze the huge amounts of data. Additionally, such skills are also vital to case interviews and real consulting work.
That means a crucial part of PSG practice must include math and reading practice – see the above articles for more details on how to calculate and read 300% faster.
Practice with video games
Test-takers who regularly play video games, especially strategy games, report a significant advantage from their gaming experience. This is likely due to three main factors:
- The McKinsey PSG is in fact similar in logic and gameplay to a few popular video game genres. The more similar a game is to the PSG, the better it is for practice.
- Video games with data processing and system management also improve the necessary skills for PSG.
- Playing video games helps candidates understand how the interface as well as the objective system of a game works – improving their “game sense”.
I am not a fan of video games – in fact, after leaving McKinsey I founded an entertainment startup with the mission to fight the increasing popularity of video games. Yet now I have to tell you to spend a few hours each week playing them to get into McKinsey.
The question is, which games to play? Here’s a list of the games and game genres my team have found to possess many similarities with the McKinsey PSG:
City-building games
- SimCity series
- Caesar series (Zeus and Poseidon, Caesar III, Emperor ROTK)
- Anno series (Anno 1404, Anno 2070, etc.)
- Cities Skylines
These are very similar in logic to the Ecosystem Building mini-game – you need to balance the production and consumption of buildings and communities, which usually have specific requirements for their locations.
The difference between these and the PSG is that most games are real-time and continuous, meaning you have the opportunity to watch your city develop and correct the mistakes – in the PSG you need to nail it from the start! With that said, the amount of data you need to process in these games will make the McKinsey PSG a walk in the park; the learning curve is not too high either, making these games good practice grounds.

Tower defense games
- Kingdom Rush series
- Plants vs Zombies series
Tower-defense games such as Kingdom Rush are near-perfect practices for the Plant Defense mini-game of the McKinsey PSG. Our basic “kill-zone” tactic in fact comes from these games.
Again, there is a caveat when practicing with games – both Plants vs Zombies and Kingdom Rush allow you to correct your mistakes by having the invaders attack the base multiple times before you lose. Both games also feature fixed and predictable paths of invasion. In the PSG, the path of the invaders changes with your actions, and if they reach your base, you’ll lose immediately.

Grand strategy and 4X games
- Civilization series
- Europa Universalis series
- Crusader Kings series
Grand strategy and 4X games combine the logic of system-building and tower-defense games (with Civilization being the best example), making them good practice for both games of the PSG. They also require players to manage the largest amount of data among popular game genres (sometimes multiple windows with dozens of stats each).
However, they are also the game with the steepest learning curves – so if you are not one for video games, and/or you don’t have much time before the PSG, these games are not for you. They are also less similar to the PSG on the surface, compared to the two genres above.

New release: Redrock Expansion (early access), an update of McKinsey PSG simulation
On September 1st, 2022, we are releasing a new product – Redrock Expansion to feature a new game of McKinsey. The Redrock Simulation can be purchased standalone or in Mckinsey PSG Simulation (All-in-one package).
McKinsey PSG Simulation is an end-to-end, most updated interactive practice platform for the McKinsey Problem-Solving Game with a 50-page in-depth strategy guide, template spreadsheets for the Ecosystem Building game, and an infinite number of practice scenarios in an interactive practice environment for both core mini-games-and a rare new game – Redrock Study.
Scoring in the McKinsey PSG/Digital Assessment
The scoring mechanism in the McKinsey Digital Assessment
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Master strategy consulting interview with coach Frederic.
Date: June 24th (4:00pm - 5:30pm, GMT+2)
Duration: 1.5 hours
Class size: 30-40 students
If you rank above the 75th percentile (i.e. top 25% of candidates), and has a good resume, you are likely to pass the McKinsey Solve Game / PSG.
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McKinsey Problem Solving Game (Solve)
The Problem Solving Game (Solve) was constructed to meet McKinsey’s changing value proposition. which promises to strive for an unbiased and smoother recruiting process. Previously, candidates had to take PST either at assessment centers or at the office, while Solve can be taken at home, which makes it more convenient for both candidates and McK.
Another factor for change was that the nature of the consulting business has become quite complex, with more stakeholders to manage in fast-evolving conditions. As a result, strong business judgment and analytical skills are not enough to solve today's business problems effectively.
Because of the factors above, Solve has taken the place of the original Problem Solving Test, which no longer challenges candidates with the dynamism that McKinsey requires.
Game Details
As McKinsey continues to strive for a smoother recruiting process, the PSG assesses candidates for adaptability and application of knowledge in uncertain environments. Crafted by Imbellus to be a game that cannot be prepared for, many hopeful applicants out there are looking for a window into what to expect.
The online game is a 60-75 minute assessment that consists of two parts (candidates play a different game in each part).
Each scenario requires different preparation, but there are tactics that can help you gain time and crack the game for all scenarios
Ecosystem Creation (Coral Reef): Objective of the game is to create a sustainable ecosystem (i.e., stable food web) in a coral reef by selecting the most suitable location and the most appropriate species.
Top Tip: Start by identifying the ideal location to build your ecosystem. Once you build the ecosystem, ensure that you created a sustainable food chain in which all species survive.
Ecosystem Creation (Mountain Ridge): Create a sustainable ecosystem (i.e., stable food web) on a mountain ridge by selecting the most suitable location and the most coherent species.
Plant Defense: Defend the native plant from the attacking predators for as many turns as possible beyond 15 turns by preventing their access with barriers or reducing their population with other animals.
Top tip: Analyze your resources and identify their strengths; then deploy them to block invaders. As you play the game, analyze behaviors of invaders and test the effectiveness of your resources to set your new strategy.
Migration Management: Identify the most efficient route for animals to migrate to reach the endpoint with the highest proportion of animals remaining alive.
Top tip: Analyze the pattern between routes and their effects on animals and optimize routes to the endpoint, including the intermediate stops.
Red Rock Study: Review objectives, answer questions by analyzing data and summarize findings by visualizing key insights for a business problem.
Top tip: Collecting information is the most crucial step, look for context, figures, and timeframes of the directions provided in the assessment. Be prepared to answer around 10 questions by filling in the blanks, hence time management and note-taking are key to success.
Disaster Management: Determine the type of the disaster and try to minimize its damage on your animals by moving them to a more convenient location.
Top tip: Identify the type of disaster and commonalities among species. Once you identify the type of disaster and common characteristics of the species, you can choose the best location to maximize the survival rate.
Disease Management: Prevent the disease to save the animals in the ecosystem.
Top tip: Start with understanding key characteristics of the species and analyzing how change in time affect different species. Once you derive relationships between time and species, finalize a list of species to be affected and identify the right treatment.
Why a Problem Solving Game?
The McKinsey Problem Solving Game occupies the space between CV screening and face-to-face case interviews. It is mandatory for all McKinsey candidates. Its purpose is to weed out those who lack the mindset and skills necessary to be an effective business consultant. By pre-emptively eliminating most of these unfit candidates before they reach the expensive (for McKinsey) face-to-face interview stage the company dramatically reduces their recruitment costs.
In theory, the new game cannot be cracked. However, the Prepmatter Online Assessment Package ensures no candidate need to go into the test unprepared. Still, many candidates wonder why McKinsey decided to incorporate game theory into their assessment of potential business consultants.
The company felt multiple-choice tests were ultimately of limited use when it came to assessing whether a candidate would make a good business consultant. And with the business landscape shifting under our feet as you read this, a better method was needed to assess the ability of candidates to think on their feet. Enter the McKinsey Problem Solving Game.
How Prepmatter Can Prepare You for the Unexpected
When you enlist the aid of the Prepmatter team to prepare for the McKinsey Problem Solving Game you will benefit from the collective knowledge who have actually taken the test. We cover every aspect of the test process including, but not limited to:
- A breakdown of the different games, their underlying logic and successful strategies
- A variety of game tips that will help you optimise your chances of success
- Other games that serve as useful McKinsey Problem Solving Game practice games
Just keep in mind that since neither McKinsey nor the game’s creator Imbellus publicize the details or mechanisms of the Problem Solving Game, and since the games are constantly evolving, it is possible that some tips or insights may not reflect with complete accuracy current in-game elements. However, we are continuously updating our guide to make sure that it says relevant.
What is included?
In our guide, we lay out exactly how Solve works with publicly available and remastered in-game visuals, as well as a host of tips to crack the games. We also provide the best preparation guide available. Our guide is continuously revised with the latest insights.
You can access the McKinsey Problem Solving Game guide as part of the Prepmatter Online Assessment Package, which includes comprehensive guides for 3 of the McKinsey, BCG, and Bain assessment models.
An 80-page guide detailing how the McKinsey Problem Solving Game works, complete with in-game visuals, and how you can crack the assessment with confidence.
Bain and BCG Pymetrics Tests
A 35-page guide on the Bain and BCG Pymetrics Tests, including how the assessment works, with in-game visuals, details of all 12 questions asked, and tips on how best to prepare.
BCG Potential Tests
4 x 23 question BCG Potential Tests, complete with answer books that have been carefully crafted by former BCG consultants.
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McKinsey Problem Solving Game (Imbellus): a Complete Practice Guide to Pass the Digital Assessment
There is a lot of secrecy around the McKinsey Problem Solving Game, aka Imbellus.
This gamified assessment is used to filter out a large chunk of the many McKinsey applicants, and it’s supposedly crack-proof.
The internet is packed with blog posts, Reddit discussions, and forum threads about the McKinsey PSG, some even contradicting.
This information overload coupled with the huge importance of the test make the whole preparation process nerve-wracking.
That’s why this practice guide strives to give you accurate and easy-to-digest information about your upcoming test.
It includes:
- A complete overview of the mini-games
- The best things to keep in mind while playing them
- The most helpful practice options available right now
- Useful tips and tactics to increase your chances of passing it
So, buckle up, and let’s get started.

Hi, I'm David, JobTestPrep's expert for the McKinsey Digital Assessment. Have a question? Feel free to send me an email at any time .
The preparation course that we recommend on this page includes a replica of McKinsey's Ecosystem Building game. It enables you to practice using a like-for-like game experience, and learn about every single rule, move and item in detail. Plus, you’ll master calculation methods and other tactics to ensure the food chain survives in your chosen location.
What is the McKinsey Problem Solving Game (PSG)?
The McKinsey Problem Solving Game, also named McKinsey Imbellus, McKinsey Digital Assessment, and Solve, is a gamified test that replaces the previous assessment, PST, in the recruiting process. The PSG consists of two mini-games lasting for approx. 71 minutes, and evaluates candidates on five key cognitive abilities.
Only candidates who pass this stage are invited to the next hiring step, the case interviews.
What Skills Does the PSG Evaluate?
The PSG evaluates the consulting traits and qualifications of a candidate and then compares them to a real McKinsey consultant. If the applicant appears similar or better than the actual consultant, they'll pass the test.
Five main thinking skills are being assessed :
- Critical Thinking : The ability to solve problems by breaking them down into smaller parts.
- Decision-Making Process : The ability to take in large amounts of information and process it efficiently to make the best possible decision within time constraints.
- Meta Cognition : The ability to monitor your cognitive processes and improve them.
- Situational Awareness : The ability to keep track of several tasks or activities concurrently.
- Systems Thinking : The ability to identify the root causes of problems and possible solutions.
Do All Candidates Get the McKinsey Problem Solving Game?
As of 2023, almost all candidates for nearly all Mckinsey offices receive the Problem Solving Game. The PST, on the other hand, is no longer in use.
Looking for a new job? Upload your CV into our AI, data-based CV Analyzer System, and get offers specifically tailored to your skillset and experience!
Get to Know the McKinsey PSG Format Inside Out
The Problem Solving Game is sent to candidates once they pass the initial resume screening, making it the second hiring step.
McKinsey has created five mini-games, but you'll need to take only two of them. The most common ones are Ecosysystem Building and Plant Defense , and there are three other less common mini-games that only a fraction of the applicants receive (outlined below).
The time limit for the two common mini-games is 71 minutes , and for the others, it may range between 60 to 80 minutes. Each game will also have a tutorial, which is untimed.
Here's an illustration that summarizes that:

Now, let's dive into each of the mini-games so you'll know what to expect on the test.
- Ecosystem Building
The first mini-game you'll need to pass is Ecosystem Building. In this game, you'll be randomly placed in either a mountain ridge or a coral reef scenario.

Your main objective in this mini-game is to build a sustainable ecosystem using exactly eight species from a collection of 39 species.
To achieve this goal successfully, you must strictly follow these guidelines:
- Terrain specs : The chosen location in the ecosystem must provide suitable living conditions for all eight species.
- Calories balance : Each species must be fed with enough calories from food to sustain itself.
- Food chain continuity : Each species must not be eaten into extinction by its predators.
The gaming platform provides specific information to help you meet these guidelines (some are seen on the game's "guidebook"):
Terrain Specs
Each location in the ecosystem has seven to eight terrain specs. You can choose a location using a pinpoint.
Of these seven or eight specs, only four can be displayed at any given time, using a checklist table on the upper-right corner of the screen:

Now, here's what's crucial about these living conditions:
Each species has specific terrain specs that have to be met. If they aren't met, the species won't survive, and you won't achieve the game's main objective.
Luckily, the species' living conditions usually come in ranges, allowing you to be more flexible with the species you choose for your ecosystem.
Additionally, each species has only two to four terrain specs , when Depth/Elevation and Temperature appear for all species:

Knowing that you only need to look at specific terrain specs on the checklist table helps eliminate species or locations that are not suitable for creating a sustainable ecosystem.
Food Chain Continuity
The 39 species are divided into producers and consumers.
Producers are plants and fungi (on the Mountain scenario) and corals and seaweeds (on the Coral Reef scenario). They don't have any calorie needs, so their "calories needed" spec is always zero.
Consumers are animals that eat either plants, other animals, or both. Some consumers are at the top of the food chain and therefore not eaten by any other species.
While creating the food chain, it's important to ensure that no species is eaten to extinction. This can be monitored using the " calorie needed " and the " calorie provided " specs that each species has (shown below).
Calories Balance
Each species has a calorie needed and a calorie provided, as you can see below:

A species lives if its "calories needed" are less than the sum of the calories provided by other species it eats (other consumers or providers).
Furthermore, the species' "calories provided" must be higher than the sum of the calories needed by other species that eat it.
The Main Challenges of the Ecosystem Building Mini-Game
Ecosystem creation is first of all a decision-making game.
You get all the information you need to deliver correct decisions so there's no uncertainty or inaccurate details.
The problem is that you have a vast amount of information to absorb, calculate, analyze, and prioritize . This includes the specs of 39 species, terrain specs of each location, and eating rules.
Some of the information is irrelevant and is there to distract you or tempt you to make assumptions . In this mini-game, you must not make any assumptions and you don't need to have any environmental, ecological, or zoological knowledge.
So, your ability to make quick and accurate calculations and ignore irrelevant data will have a great impact on your performance.
- Plant Defense
The second mini-game you'll most likely encounter is Plant Defense, also known as Invasive Species.
Plant Defense is a turn-based mini-game (similar to popular Tower Defense games). Your main objective is to defend a native plant that's located at the center of a 10x10, 10x14, or 12x12 grid from invader species, using defensive resources for as many turns as possible .
This mini-game consists of three maps, when each map is divided into two - the planning phase and the fast-forward phase. McKinsey recommends allocating 12 minutes per map, which makes it 36 minutes in total.

The 36-minute time limit is not fixed though, as it depends on how long it took you to finish the first mini-game, Ecosystem Building.
Many candidates mention that the Plant Defense game is more challenging than the Ecosystem creation. So, keep that in mind while taking the first one and plan your time wisely .
Now, let's take a closer look at the different elements and resources of this mini-game:
Your base is the native plant that you have to defend from invaders at all costs. Once an invader reaches the base, you lose the game.
Note that eventually, everyone loses, and you can't hold your base forever. But the more turns you manage to survive, the better .
There are two types of invaders in the game - Groundhog and Fox. Their movements on the map are the same, and the only difference between them is the terrain type that holds them back (more on terrains below).
Once an invader appears on your map, it will choose the shortest path to reach your base plant. This path will be shown as a yellow arrow .

There are three types of terrains in the game:
- Forest : Slows down the Groundhog for one turn
- Rocky : Slows down the Fox for one turn
- Cliff : Blocks both the Fox and the Groundhog from passing this square

Each terrain holds one grid on the map, and you cannot place terrain on a grid that already has another terrain or a defender on it (more on defenders below).
As opposed to terrains, defenders don't just slow down or block an invader, they eliminate it for good.
There are several defenders you can use in the game: Bobcat, Falcon, Wolf, Python, and Coyote.

Note that you won't see all of the defenders at once.
Each defender has two important specs you must take into account:
Range : Each defender can cover a pre-determined number of grids on the map. For example, a Python can cover only one grid, while a Falcon can cover as many as 13 grids.
Damage : Each defender can cause specific forms of damage to an invader's population. When an invader attacks, you'll be able to see its population number and the damage that your defender can cause him. A Wolf, for example, has a damaging impact of 60, while a Falcon has only 20.
The Main Challenges of the Plant Defense Mini-Game
In this mini-game, you have to make decisions based on limited information and face unexpected events (like new invaders from any direction). Also, you must achieve two simultaneous objectives - survive each of the turns separately and for as long as possible.
This is the complete opposite of the Ecosystem Building game, in which you have all the data in front of you, and you have just one objective.
Two things that can help you overcome these challenges are (1) preparing for the unexpected events that will happen during the game and (2) planning low-risk solutions based on your resources (terrains and defenders).
The prep course that we recommend on this page has the closest simulation possible to the actual Plant Defense game. It has the same gameplay, invaders, and resources, and it's based on the same algorithm that appears on the McKinsey Problem Solving Game. This will enable you to learn the most effective tactics to ensure your base plant survives as many turns as possible.
Alternative Mini-Games
As of 2023, the Ecosystem Building game is constant, but the second mini-game may vary in rare cases. This means that there's a slight chance you won't get the Plant Defense mini-game, but rather one of the three we show below.
Disaster Management
In the Disaster Management game, you have to identify what type of natural disaster has happened to an animal population in an ecosystem.
Then, based on the data and information given, you need to choose a different location that will ensure the survival of the ecosystem.
The Disaster Management mini-game has only one objective - the sustainability of the ecosystem, similar to the Ecosystem Building mini-game.
Disease Management
In the Disease Management mini-game, you have to identify patterns of a disease within an ecosystem and predict who will be infected next. You can then use the information given about each species to help you solve the problem.
Migration Management
Migration Management is a turn-based puzzle game. The candidate must direct the migration of 50 animals while helping them arrive at their destination with minimal casualties and with a pre-determined amount of resources.
How to Beat the McKinsey Problem Solving Game?
The proven way to beat the McKinsey PSG is by properly preparing beforehand.
There's no way around it. That’s because the mini-games include an immense amount of information, rules, and patterns you must master . And they require you to use tactics and strategies that are not obvious and take time to plan and execute.
All of that is under great time pressure and the high stakes of possibly failing it and losing an opportunity to work at McKinsey.
Now, there are a few practice options you can use to get a better understanding of the PSG and improve your chances of passing it, with the PSG Interactive Simulation being the most accurate one.
McKinsey Problem Solving Game Practice Options
PSG Interactive Simulation
Currently, the best practice option is a replica of the PSG itself. And there’s only one such product in the market:
The McKinsey Problem Solving Game Interactive Simulation.
This PSG simulation is an interactive platform that includes accurate practice for every part of McKinsey’s PSG. It mirrors how the actual game scenarios look like, what each button does, how the logic of the games works, how it generates the data, and more.

It has both a full simulation option (two mini-games, 71 minutes) and practice modes to use the gaming scenarios without time constraints to learn the needed problem-solving skills and tactics.
And at the end of each practice session, you’ll receive a detailed analysis of every move you made, as well as a “product score” and a “process score.” Meaning, your final scores plus scoring for every step in the solving process:

Moreover, there’s a 50-page manual that accompanies the simulation. It includes additional strategies and step-by-step solving tactics to help you nail the test.
Preparation Guides
Several preparation guides offer information, insights, strategies, and other resources to help you get an in-depth understanding of the Problem Solving Game.
While these guides enable you to understand the theory behind the gameplay and learn different solving strategies, they don't give your an authentic "hands-on" experience .
This means that when you face the actual test, you'll still need some time to get used to the interface and how it works and understand where all the data is hidden. And while you're trying to figure out how to use it and become overwhelmed, the timer starts to tick.
On top of that, a lot of the information provided in these prep guides is covered in this article or in other free articles you can find on Google.
Practice with Video Games
Some candidates mentioned that the McKinsey Digital Assessment can be overwhelming if you aren’t used to computer games in general.
On the other side, gamers who play frequently - especially strategy games - have a shorter learning curve when taking the PSG.
That's because they tend to be better oriented to game settings, and they find what to do next and when to do that quicker.
That said, certain types of video games will be more beneficial when preparing for the McKinsey Problem Solving Game. As a general rule, the more complex and similar a video game is to the PSG, the better.
Here are several video games that have some similarities to the McKinsey PSG gameplay:
- Zoo Tycoon - similar to Ecosystem creation
- Planet Zoo - similar to Ecosystem creation
- Kingdom Rush - similar to Plant Defense
- Roller Coaster Tycoon - similar to Ecosystem creation
- Planet Coaster - similar to Ecosystem creation
- Plants VS Zombies - similar to Plant Defense

Image from Zoo Tycoon 2
These video games are a fun way to get used to the type of strategic thinking that’s required on the PSG and can help develop your game sense.
However, they are not a replacement for a proper prep plan that includes all the elements you need to master to succeed on the PSG.
Tips to Improve Your Performance on the McKinsey Problem Solving Game
Here are several specific tips to help improve your overall performance on the test as well as tips to avoid any disturbances that could hurt your score:
#1 Sharpen Your Mental Math Abilities
The ability to make fast and accurate calculations can help a lot in this Problem Solving Game. That’s because one wrong calculation might ruin your carefully built Ecosystem or cause an invader to reach your Native Plant.
There are several free apps and sites, like the renowned Khan Academy , that can help you improve your math skills quickly.
#2 Learn Fast Reading Skills
Mckinsey’s PSG requires you to absorb and analyze a tremendous amount of information under strict time constraints.
Fast reading skills come in handy in this test and can help reduce the amount of time needed to understand the numerous guidelines of the mini-games.
There are certain apps and browser extensions that allow you to practice this important skill , even on the go.
#3 Focus Only on What Matters
Don't get nervous when you first see the immense amount of data on the mini-games. That’s because a lot of the data is irrelevant, and you’ll be only using some particular parameters .
For example, in the Ecosystem game, you’ll only have to use specific species and terrain specs for your calculations, while ignoring others that are there only for distraction.
In the complete PSG Simulation Practice , you’ll see how to remove as many as 70% of the irrelevant data and remain just with the information that matters.
#4 Ignore Outside Information
While taking the assessment, especially the Ecosystem game, try to ignore any outside knowledge and information.
For example, if you’ve learned biology or zoology and you see that your food eating rules don’t seem logical but the numbers are correct, always go with the numbers .
If you start to rely on previous knowledge, you might get confused and mess up your progress in the game.
#5 Learn to Solve Problems Like a Consultant
The PSG measures your consulting traits and compares them to a model McKinsey consultant.
That’s why learning to think and solve problems like a real consultant can help you pass this assessment.
Two main problem-solving skills you should practice are decision-making in fully controlled situations and with limited information.
Both of these skills can be trained using complex strategy games (examples are mentioned above) as well as practicing with the full PSG interactive simulation .
#6 Cut Down on Calculation Time Using Microsoft Excel
Mental math is an effective way to make calculations in the mini-games.
But as you’re only human, it’s not error-free. That’s why using a calculation tool, such as Excel formulas, can be a great way to make super fast and accurate calculations.
You can use it to gather all the relevant data, arrange it with columns and formulas (even in advance!), and turn the whole process into a no-brainer.
That said, you’ll need to use another monitor (preferably with a different browser) or another laptop since the assessment’s platform will take over your entire screen.
#7 Prep Your Hardware and Internet Connection
The last thing you want during the assessment is a “blue screen of death.”

It may happen if your hardware is not strong enough, since the McKinsey PSG is pretty demanding in its system requirements.
Any computer that is more than five years old or without an HD screen will likely encounter lags and performance drops.
Also, you must have a fast and stable internet connection. If you get disconnected in the middle of the test, you might need to start all over again or even re-schedule for another testing date.
Unfortunately, McKinsey doesn’t disclose your test results. You will only get an email informing if you’ve passed and moved to the next hiring step (consulting case interviews) or not.
No explanations and feedback and no component score. So, there’s no way of knowing how well or poorly you did.
However, if you get the PSG Practice Simulation , you’ll have a mock grading system that monitors your end results and behavioral patterns.
This will allow you to track your progress while you practice for the test and see which areas demand improvement.
Why Did McKinsey Develop the Problem-Solving Game?
McKinsey created the Problem Solving Game as an unbiased way to identify candidates from around the globe with strong cognitive abilities. The former assessment, Problem Solving Test (PST), was less challenging for candidates who were familiar with standardized tests, such as SAT and GMAT, or used the numerous mock tests found online.
The PSG, on the other hand, is supposedly crack-proof. That's because it takes into account the approach you use to solve the problems, and not just the final solution. This seemingly removes any lucky guessing and shortcut techniques that were common on the McKinsey PST.
While on the PST you had just your final score, on the PSG your score is comprised of dozens of scoring criteria apart from your final result , including mouse movement, keystrokes, and clicks.
McKinsey can analyze these factors for every recorded candidate, which allows them to compare candidates more fairly.
What Does Imbellus Mean?
Imbellus is a company that creates immersive simulation-based assessments to assess cognitive processes. To develop a new testing format for the McKinsey recruitment process, they've teamed up with McKinsey consultants and UCLA Cresst psychologists.
In 2020, Imbellus was purchased by Roblox , an online gaming platform, to help sharpen its recruitment practices.
This was an in-depth prep guide for the McKinsey Problem Solving Game. It gave you an overview of the different mini-games, explained their main challenges, and offered some useful solving tips.
Additionally, you saw the best ways to prepare for the assessment, when the PSG Practice Simulation being the most realistic and accurate one.
You can get more information about the practice simulation on this page .
- What's on This Page
- What Is the McKinsey PSG?
- How to Beat the Games?
- Best Practice Options
- 7 Tips to Boost Your Performance

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So in this article, we will teach you how to ace the McKinsey Problem Solving Game and progress through the recruitment process
McKinsey Problem solving game is a game-based assessment that leverages artificial intelligence and algorithms to score candidates
McKinsey Problem-Solving Game (also known as McKinsey Digital Assessment) is a gamified test designed by Imbellus for the consulting firm McKinsey
The McKinsey problem-solving game (Solve) assesses candidates for adaptability and application of knowledge in uncertain environments
The test created by the organization Imbellius is also known as the McKinsey Digital Assessment or Solve and is a gamified assessment evaluating candidates in five areas. The McKinsey PSG differs from other tests
This is a complete prep guide for the McKinsey Problem Solving Game (PSG), aka Imbellus or Digital Assessment. Get helpful tips, practice options, and more