Your game is super fun! I love all of the weapons like the green shell. All of the weapons feel unique and special. I enjoy the arena combat of the game, it makes everything close quarters and super intense. I also appreciate you showing where enemies will spawn, that makes the entire game far better in my opinion.
If you wanted to continue to build, some sort of health system would be nice. The one hit kill seems kind of brutal. Maybe you could experiment with levels with a set type of enemy. Between levels the player could spend some score on new weapons. You could have the traditional progression tree or a random weapon giver.
This game is fun already and has tons of potential. I can't wait to see what you do with it in the future. Best of luck on the jam and with your future game dev projects!