Dude this is amazing, the aesthetic and the level of polish is incredible! Love the glow and the level start effects.
I also like how the guns are varied and the bullet impacts etc. feel so satisfying. Sound is good too, and using the deck of cards as level select is a cool idea.
I would tweak one or two things - like dead enemies should be a bit more distinct so they aren't so similar to live enemies. And having a bit more guidance at the start on what I need to do would be useful. Shorter, snappier levels might keep the pace high as well, otherwise there's a bit of wandering about.
But overall, I've played a bunch of the games from the jam and this in the top #3 no question. The level of polish and stuff is awesome.