I have 0 complaints with your puzzles. I had a lot of fun with them and never felt clueless and/or at a loss. The only thing I can suggest is that when you make harder puzzles in the future, playtest them a bunch.
My only real complaint (& I already mentioned this in a comment on your game) is that mirrors can get stuck, forcing you to reset. This is an easy fix though with a grab mechanic (or something more clever you come up with!).