I have a question about starting out with skeleton, or base code, prior to when the compo begins. I've always started with a completely empty slate with no code written, no copy+paste, and no predefined structure or scenes to my app (MainMenuState, GameState, EndingState, etc.) Obviously I know that I can't start writing code or drawing any art until it begins.

How strict are the rules regarding this? Let's say I have code written for a previous LD that controls character movement. Can I copy+paste this in future LDs? Also, if I were to use Godot or Unity am I able to create the basic scenes before the compo starts?