Man, I really liked all the little touches you managed to get in -- the watery sloshing of the health, the shader effects, the way the enemies stuck to you when they "bit" you. Lots of little polishes are really nicely done.
Concept wise, I do love that the player is their own worst enemy - bullet hells are not my forte at all, but I love that effect, of realizing that missing or firing too much is going to come back and haunt you in the end.