The platform-puzzle game mechinic is quite good (plus it matches the theme).
i do find something which may be misleading and may need some visual to improve. There is one puzzle that player simply needs to fill some stone and raise the water level. The water is visually not high enough to cover the upper block, but it does in game logic, triggers the gem and pass the level.
Maybe it just needs some polishing. Anyways, good job, my friend.