This is stylish! I'm only going to nit-pick because I'm jealous:
- those air enemies were quick and tough to hit. I also felt the collision wasn't dead on- but maybe I just suck at it!
- looks like some trees were spawning a little far on the right side
- maybe a short amount of time where you could be invulnerable after a hit would help
Again, stylish little game with good controls. Great job!