Patch release.
I found what was causing the problem. It's the hierarchy. It's acting very strangely. All I did was open the project on version 476 and get an error. Before that, I can't say which version I was on because I don't remember. It's higher than 470.
And after that, my project crashed.
The problem: I have an object that has a hierarchy, a sprite, a sprite, and text. This object is created in a loop when the layer starts, and it completely crashes the game if the "create hierarchy" checkbox is checked. I'm also using a template.
Removing the hierarchy from the object works fine, or unchecking the "create hierarchy" checkbox works fine. I'm also getting some strange bugs: the project randomly crashes while I'm moving the object, and if I click "remove hierarchy," a copy of the object appears on top of it in the creation layout... WTF? This hasn't happened before. Removing the hierarchy removed the green arrow and that was it. But why do I need another copy on top? That's very strange.