I always like to see a juicy game in such a short jam like this. Good work on the game-feel!
I would have liked to have seen more variety in the types of weapons the player receives. There are changes in the damage, fire rates, and "magazine size" (I think), sure, but ultimately they're all used in the same way and have the same consequences. Weapons that force that player to change their playstyle, like a very short range shotgun that makes you get aggressive, or a grenade launcher that launches a bomb that will kill the player if they're hit by the explosion, or a weapon that shoots a spiked ball that bounces around the screen and hurts the player if they touch it. That, combined with a system where I see the next weapon I'll be receiving, would open the possibility of interesting strategy and tense, wacky scenarios.
There was a game in the GMTK jam in 2018 called Ratatatatouille that had a similar idea, and executed on it in the way I described.
It was a fun and satisfying game though! Good job :)