gamemaker-risk-of-rain

Tools for unpacking and decompiling the GameMaker data file for Risk of Rain 1, called data.win on Windows, data.ios on MacOS and game.unx on Linux.

Executables

Examination

cabal build examine
cabal run examine -- FILE

^{(where FILE is the data.win/game.ios/game.unx file)}

Outputs data file information to stdout.

Decompiler

cabal build decompile
cabal run decompile -- FILE

^{(where FILE is the data.win/game.ios file)}

Disassembles and decompiles game's source code, outputting K&R indented GML to stdout. Note that this is only available for Windows and MacOS builds of the game; there was a period when Hopoo distributed YYC-compiled versions of the game, but they stopped as it caused crashes.

Honorable mentions

Kudos to the Undertale datamining squad for sharing their findings. Without them decompiling the game would take even longer than it already did and would not be nearly as successful. Links to Undertale stuff:

• Data file format and 0xF instruction list: tomat.dev/undertale;

• Detailed 0xE instruction list: github.com/gm-archive/acolyte/wiki.

• Corrections to data file format and 0xF instruction list: github.com/krzys-h/UndertaleModTool/wiki.

Questions

Q: Can this decompile games other than Risk of Rain 1?

A: I tried like five and all of them seemed to use bytecode 0xE, while Risk of Rain 1 uses 0xF (if I had to guess people just don't update because updating GameMaker breaks the project). There are major structural differences between the two, therefore even the naming of the modules in the package is GameMaker.RiskOfRain.*. If you want to decompile a different game, handroll another setup, you're most certainly not using Haskell either way.

Q: Why is this in a separate package and not inside a game build?

A: Because I feel like it makes for a nice little unit by itself, so even though it is practically useless outside of a game build, it can still exist as a separate package. Seeing how I've been experimenting with making a game for the past two years eternity, I'm not even sure I'll make a working videogame ever, so perhaps someone can use this to figure out how to unpack a different game.

Contact information

The only contact channel I have is Github, at least as of the time of writing this.