Great idea for a game! At the beggining of the jam I was also thinking about making a similar game, and I gotta say this one is very nicely realized. The upgrades are fun and the general gameplay loop is very much engaging. My main issue is that it was often hard to tell where enemies are. I would get shot out, and I kind of had to circle the shooter and wait for the enemy to show up. Maybe some sort of arrow indicator could be nice for that in the future. Other than that though, good and nice to play entry. Good job!