I'm sorry for bad performance on fourth level. I pulled an all-nighter to add actual levels to the game, submitted at 6 AM local time. So no optimizations whatsoever. It should work better with the executable.
This was my first time using Godot (and first in ten years for any game development aside from small experiments), so there was alot I had to learn from scratch. Fortunately Godot is very easy engine/editor to build with, I can recommend.