Controls are a little bit off. I got used to the fact that WSAD works relative to where I am poiting my mouse, but then found that if you aim to the side, player character doesn't shoot at mouse, but slightly above it. Aside from that it is also a shame that there is no sound in the game. Trust me, that even some little click noises can make the whole experience way different.
Aside from that theme is matched pretty well, ammo collecting mechanics is fun, and the ammo particles look great.