The "clocky" sounds make it really zen, but for some reason the rotating parts lost it for me. I skipped the level 6, not because it was hard, but because I somehow felt it wasn't fitting. Don't put skulls in a peaceful game!:P
Also don't know if its really needed to have 4 puzzles per level, one or two should be probably enough, as its sometimes annoying to go back and forth with the configurations (especially those rotating for me). But overall simple but effective idea, could be made into full game, gj