Really clever puzzles! I really needed to put on my thinking cap in this game, for level 5 especially. I think a sign of a good puzzle is to make the player feel confused at first and then silly for not getting it sooner once they've solved it. Or at least, that's how I felt and I liked it. :D
Sometimes Plarc was unable to move when other boxes were stacked on top of it, but other times it could. I'm not sure which result was the intended one.
If you liked it you can try my another puzzle https://dustdfg.itch.io/boxplatformerdemo with similar (but very different) mechanics
If we forgot about the fact I don't know why top box moves with bottom box (because I didn't program it at all. The engine does it but where, when and why?), so the moments where you can't move when another box on top of you is a bug of default godot physics after I changed it to rapier2d engine it started to work
EDIT: Just found the place where bottom box moves top box :D
