Wow, the twist really got me. I dont wanna spoil it, but for anyone else make sure you get to level 5!
I would recommend trying to add some kind of recovery mechanic. Its REALLY annoying having to restart a level because of a small mistake. The puzzles feel really easy, its more just a tedious loop of trying not to make a dumb mistake. Its a classic concept though, I think you just need to spend some time refining the core gameplay. Look at some other games with this type of puzzle for inspiration.