Clever puzzle game! Love the idea of not having control of some keys unless the box is over it. Very "baba is you" in that regard. The levels are challenging but don't feel impossible (I did have to quit eventually because I was absolutely stumped by one of them haha but that's on me) and there's instant feedback when you feel you've made a terrible mistake. Always a great sign of well designed levels.
As others have said I would have loved an undo button, it would make backtracking and redoing mistakes a lot easier than remembering what steps I took and starting over completely.
All in all great work!