Lab Rat

A Puzzle Generator for Portal 2

by Kyle Schouviller

Lab Rat is a "mod" for Portal 2 that generates random puzzles for you to solve!

Download Version 0.1
Get the code library

What is Lab Rat?

This is the initial release of a "mod" I'm building for Portal 2. It's not a mod in the traditional sense - no code within Portal 2 has been changed, nor have I changed any content or UI (yet!). Lab Rat is a program that runs in the background behind Portal 2 and generates puzzles for you to solve. Currently it generates 3D mazes, which can be quite difficult!

This is an early release, but I wanted to get it out there and get some feedback so I can iterate on it. I hope to eventually build this into a puzzle generator that can create interesting puzzles - or at least interesting starting points for you to build your own puzzles on top of!

How to Play

Make sure you've opened the Portal 2 puzzle editor at least once. Run Lab Rat, select your difficulty level (the large number at top - I suggest starting at 1), then click "Run Portal 2". On the main menu of Portal 2, click "Community Test Chambers", then select "Create Test Chambers". Within this menu you should find an entry called "Lab Rat" - open this map, then press the "Build and play puzzle" button at the top to play the maze! Every time you exit the puzzle editor and open the Lab Rat puzzle, it will be replaced with a new maze (with a new difficulty, if you've changed the difficulty while it's running). Good luck!


You'll need to have updated Portal 2 to the latest version and opened the puzzle editor at least once. It's also Windows-only for now.

Additional Info

Lab Rat is developed in C# and runs on .NET 2.0. I've developed a full code library for working with P2C puzzle files that is available at

If you have any questions, please contact me. If you'd like to see my other work, please visit my website.