So pretty... Figuring out how to use the shadows well was satisfying. Some levels seemed slightly longer than 20s, but not a problem - on the contrary, I wish the levels were at least a smidge longer so we had more time to take in the scenery...
The music was pleasant and relaxing, I think it turned out well - no need for you to worry about lack of experience. I'm sure you'll get even better as you keep experimenting.