This is very well executed! Puzzle games are hard to make and I thought yours did it very well. The puzzles didn't feel too challenging (except maybe that key one, struggled with that!) and the way you laid out every level made it very clear for the player what they are supposed to do - which I like! It feels like a tutorial without a blob of text. I did notice one issue - it looks like you only grab the mouse after some movement input, and this resets after interacting with something. For example if I click E on an item, then when I go back I can move my mouse off screen. Otherwise it was great! The environment secretly changing behind you is a nice, subtle touch as well.