Studying how the actual game works, in gsc, is very useful as well.
And also allows you to do all kinds of cool stuff, like replace some behavior when something happens, or maybe re-use some of the gsc that's already in the game so you don't need to custom make everything.
The stickied post in here has a download to a gsc dump. Then also get get some program that searches for text from inside multiple files. Useful when you're looking for something specific, or want to see where some function is defined, where it's called, etc etc etc. Been using "AstroGrep" myself to do this.
