This game is so, so, SO much fun. Hitting a 5x shot feels incredibly satisfying. Simple mechanic, but incredibly satisfying to nail and master it. Keeping a 5x going during the intermission phases of bosses such as The Meat and The Creep to then unload as soon as they show up was a really nice feeling, and great job on the visual and audio feedback when you land one of those shots.
I also really enjoyed the game's presentation, the Office sequence adds a lot to the game and is really cool, I enjoyed going through all the e-mails and it's nice to see you some small worldbuilding in a Jam game, the e-mail from mom was super cute. And then, as I was already really enticed by this initial presentation, I load up my first boss and see "Tip: Judging by your Office, you are probably an alcoholic" - that was the cherry on top, loved it!
You have something great here that can definitely be expanded on, really fun game.
Very, very VERY small nitpick: I feel a bit weird being able to press R to reload while at a full magazine; I mean it's not wrong per se, and could be a design choice, but at this point my brain has been conditioned by shooters that when you press R at a full magazine, nothing happens