Important
DELTAModKit is in development. If you find any issues, you can help out by creating an issue or opening a pull request.
The most robust, feature-complete DELTARUNE GameMaker Studio 2 decompilation / port, enhanced with a multitude of tweaks designed to make the game easier to mod.
Caution
This project does NOT allow for piracy of DELTARUNE Chapter 3, 4, or 5. It is simply a base from which you can start building your own DELTARUNE chapter/fan game. Most assets which have been included in the project can be found in the free Steam demo for Chapter 1 and 2.
To start playing around with DELTAModKit, you have to download GameMaker. The project was originally created on GameMaker Beta, however any relatively recent version of GameMaker (such as the 2026 LTS) should work.
- Clone the repository onto your PC.
- Create a
datafilesfolder at the root of the project. - Copy the
musfolder from your Steam DELTARUNE installation intodatafiles/mus. - Open the project in GameMaker.
- To activate debug mode Switch Config from "Default" to "Debug"
Caution
Light World (Hometown) rooms have not all been fully ported yet, so beware of missing text and certain rooms not existing.
The hearts of the modular reimplementations of the character, item, spell and equipment systems all live in the folder Custom > Scripts > Configs. I tried naming everything in an easy-to-understand way, but feel free to reach out if you encounter any issues. Provided in the Custom > Objects folder is an example cutscene for working with the Cutscene System and some helper markers to assist with character placement in cutscenes
All sprites and most code contained in this repository was created by Toby Fox and Royal Sciences LLC.