Nice idea. Finished with 4 bullets left. I like the physics of the game.

Really cool casual game.

It is a very good game. Overall moving by recoil is a good idea and it would be more challenging to add some enemies that move in the medium or top.

There is a lot of potential in this game, basic fire to kill enemies and keep yourself up and moving was well done, and with the right sound effects, it could be awesome.  I would expand the play area and have a level exit somewhere to be found. Each level could then have different traps, and spikes to avoid, enemies killed give boosts, points or buffs. The visual style works well, but try different colour palettes to make it more striking.