Nice submission! I think it's could also have some mechanic around making goals, and also the pointing system / ending condition was not clear enough in my opinion, but it was fun to play.

The theme was respected and the game mechanics were interesting with the reusable projectiles. It was also more interesting when another opponent spawned. I expected the balls to bounce but it was ok. I had an issue with enemies spawning on me so maybe make a collision detection around the player and if enemies wanting to respawn are inside of it make them not spawn. Since they wouldn't spawn if you stay in the middle you can add more spawn points too.

I hope these solutions would help you, cheers!

The ammo mechanic is pretty interesting and fits the theme well. Maybe if the balls bounced off the walls, I could plan my shots so that the ammo bounces right back into me. I like the quick arcade-y feel of the game too. Sometimes I would run into an issue where the enemies would spawn on top of me and I'd immediately take damage, so that hindered gameplay a bit. Overall good concept! Mashing up a sports and shooter game definitely has some potential.