Really nice work on this one!
Feels good to shoot and the graphics are kinda interesting! (I see the inspiration lol).
I could go on about some specific stuff that i disliked, but I think what lacks here is "meaning". Its kinda hard to explain but I feel that all the features aren't really impactful or important, and I think every single feature (graphic, mechanic, etc) should matter and make sense as a whole.
Also, I feel that is kinda annoying to click a button to pick-up the upgrades as, again, it seemed there wasn't much "meaning" for not to pick them up.