Well then, finally got a hold of GM Studio, aaand..
Nothing in my template works. Or at least, a lot of it doesn't. So I'm basically starting from scratch again.
Which is fine, really. The important thing isn't carrying over the code, but the ideas behind it all. How I'll handle collisions, how top handle the player's actions, etc. Important stuff like gamepad compatibility, saving/loading, and a couple other things will be carried over, but for everything else, I'm probably better off starting from scratch with what I know from Eroico.
Time to get back to it.
Edit: Actually, it turns out they removed a lot of stuff I sort of relied on. Looks like I've got a bit of figuring stuff out to do -___-