Although you were going for the style of a Game Boy game, this game's aesthetics actually remind me a lot of vector arcade games, like Battlezone or Tempest. Taken like that, it's a fun arcade-style shooter in a visual style that's rarely seen. The mechanic of absorbing enemy shots as ammo for your own weapon is interesting, though it was occasionally a bit frustrating to be unable to fire at all; it would be nice if your ammo regenerated at a slow rate, so you aren't completely helpless if you run out and there's no bullets on screen.

The graphical style of this game is really interesting and unique, it doesn't necessarily feel like a retro game, since I don't know of any consoles that have graphics that look like this, but that's not really a bad thing. I did like the idea of deflecting enemy shots to gain ammo, but I found that even conserving my ammo and deflecting as much as possible it was nearly impossible to have enough ammo to beat more than a few enemies each time, especially since it seems to take around 8 or so shots to kill something, and I can only at most deflect maybe one bullet every two or so seconds, so I think this would work a bit better with more powerful and slower firing player shots, or getting more ammo per deflection. Anyways, nice game overall, and great job with the crazy graphics!

The blurry lines are a cool effect.  Maybe the tubes in the machine are cursed.  Maybe this space captain's pre-combat ritual is the same as the guys from Fury Road. 

The first round, my instinct was to hold down the shoot button, which quickly became "oh no ammo is a thing".  The second go through was a lot more tactical and timing the shield bounces makes for a totally different feel.

Maybe, given more time, the player could switch between a typical unlimited ammo shoot 'em up ship, or the bouncy shield ammo one, and have two totally different play-styles to choose from.