Cool little game!
Graphics are minimalistic but for a game jam it doesn't need to be more. Everything fits good together and has just enough detail. The camera effect is also well done. If you want to improve your graphics even more and make it a little juicier you should add more particles. For example an enemy dies it just disappears, maybe you can add some effects here. The damage effect on the other hand is well done.
Audio is fine, good music and sound effects. In a jam you have little time but a settings menu for sounds and music is always a handy feature.
Gameplay feels polished. When you shoot and stand still it feels responsive and accurate but as soon as you begin to move it's very hard to hit something. Maybe add a little bit of auto aim to the player so it feels like you are hitting more and not just shooting on good luck. What you can also do is make them easier to kill, giving them less health and just spawning more of them.
User Interface could use a little bit more polishing. I know it's a game jam and that's not the main focus here but if you want to improve your game after the jam I should change it. The intense red and blue color don't really fit together. Further more I like the font and the dead screen is really funny :D. Also nice that you added this distortion effect. I should also add some music or sound on the main menu.
Overall a good game. It's not because there's a lot of feedback that you made a bad game! I'm just here to help you improve your game. Either way well done!
(Deserves some more ratings)