Cool little game, you even went out of your way to generate the levels too.
Cute art, nice music, straightforward game-play. Perhaps a little bit of feedback when hurting an enemy? At first I couldn't tell if I was hurting the enemy till it died.
Also I need to learn to read, I was so confused when I suddenly stopped being able to shoot, then saw the main menu specifically told me ammo is a collectable. Oops.