This codebase can be used to build a custom version of Celeste on macOS and Windows. The source files were generated using JetBrains Rider.

After changing some constants in Player.cs, I recorded this video:

https://www.youtube.com/watch?v=XNC5gJCAyKQ

• copy C:\Program Files (x86)\Steam\steamapps\common\Celeste\Content to Celeste\Game\

• run Celeste\Game\Celeste.exe

• Install mono:

brew install mono

• copy ~/Library/Application Support/Steam/steamapps/common/Celeste/Celeste.app/Contents/MacOS/Content to ./Celeste/Game/

• run ./Celeste/Game/Celeste

Let's do some basic modding. We're going to make Madeline climb walls 3x faster.

• Clone the repository: git clone https://github.com/shawwn/Celeste

• Install the Content folder. (See the installation steps above.)

• Open ./Celeste/Celeste/Player.cs in an editor.

• Change the following code:

        private const float ClimbUpSpeed = -45f;
        private const float ClimbDownSpeed = 80f;
        private const float ClimbSlipSpeed = 30f;
        private const float ClimbAccel = 900f;

... to this:

        private const float ClimbUpSpeed = -3*45f;
        private const float ClimbDownSpeed = 3*80f;
        private const float ClimbSlipSpeed = 30f;
        private const float ClimbAccel = 3*900f;

• Open Celeste/Celeste.sln in JetBrains Rider

• Click Build -> Build Solution

(You might want to make sure the configuration is set to Release | Any CPU, but the defaults will probably work fine.)

• if you're on Windows: run Celeste\Game\Celeste.exe

• if you're on macOS: run ./Celeste/Game/Celeste

• Climb some walls!

• Experiment with changing the other constants in Player.cs. You can change things like Gravity, MaxRun, and DashTime.

• Comment out some code in the player's update loop and see what breaks. This is one of the best ways to learn how a codebase works.