What version of GameMaker are you using? The source code should be there, but it's only for GameMaker Studio 2.
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Oh, it was never meant to be played outside the jam it was created for. I deleted the link because so many people took an interest in it and I felt that it wasn't going to meet their expectations (many downloads, 0 feedback). I made the link available again if you want to try it, but it is really just a confusing prototype of a concept, not a real game.