Boom! Welcome to the world of game jamming, we hope you stay and keep making cool shit. This is a nice little run-and-gunner, the sounds used are sooo juicy and work really well along with the blood splat particles. Sometimes I'd kill a Slop and it'd give me three points which I'm unsure of why, something to do with how fast you kill them?
There are some things that could be polished to add to a nicer game feel: camera shake, text popups of how many points you got from a kill. This would make the game feel and look sicker and thicker, but it wouldn't necessarily make it a nicer feeling experience. The one thing I would suggest changing when it comes to game logic is making sure that enemies can't spawn within X units of you, there were a few times when a Slop would spawn right where I am, killing me instantly. I found that the ideal strategy was to just hug the wall. Having them spawn outside of the camera view would give the player some time to react to approaching enemies.
All that being said, this is a solid first jam entry! Keep at it!