I’ve thought about this problem creating a system to save game state. The issue with assigning a UUID works until you have dynamic scenes added to the game at runtime. The nodes in those scenes will all have the same UUID. In the end I ended up just using the paths and saving the fact that the scene that data is being saved for is dynamic. Then the system sees this and re-instances the scene and adds it back to the tree. (A slight adjustment to the path must be made as Godot will create nodes with the at (@) symbol in them, but you can’t do that yourself.)

You can see this in action at my demo repo on github.

GDQuest has some demos that may be applicable here. I’ve found four looking through the list at https://www.gdquest.com/tools/: Godot 2D Builder (simulation demo), Godot 2D Rhythm Game, 2D Space Game (top-down space mining demo), Godot 2D Platformer, and Godot Open RPG. Looking through their github some of these appear to only be Godot 3 though.