It is fun to play, relaxing music and the great things is - difficult increase smoothly through the game process.
Here are few things i think can improve:
Make environment transparency when character moving along them, sometimes i hard to see character.
Menu and hint can be ways of presenting more clearly to player. Sometimes, i forget what keys to use, and cannot find in-game and need to restart.
Movement. I feel little difficult to control. Maybe config the character camera to more natural and make the character turning more smooth?