Heya, this was a pretty cool game, the rock music actually.. surprisingly.. fits! I have a lot of good things to say so let's go through them:
1) Damn good gameplay. It's simple, it's clean. Shoot to stay afloat, shoot to kill, shoot to evade. All encompassed under 1 mechanic, and most importantly; it feels GOOD to play. Absolutely brilliant!!
2) The sound is actually quite good. It gives the gun a lot of OOMPH, especially since the guy is literally propelled by the gun. I think if you have screenshake everytime you fired the gun, it would really help sell the game feel here and add a LOT of juice.
Some major gripes are:
1) Inconsistent resolution for the pixel art background and foreground elements. It's honestly quite minor, but it's definitely going to be a barrier of entry to polished games if you plan to take this further than a prototype.
Otherwise, I love the game! It doesn't quite fit the theme in my opinion but it's good fun!