Fun to play, and I definitely think the player skill buy breadth is really impressive for a short game jam! That said, I think maybe cutting back somewhat on scope to have more time to focus on really dialing the balance in might have served this game better. Some of the improvements feel like traps, especially anything that lowers your firing rate, as the tiny swarm enemies on wave 4ish will obliterate you with no recourse.
That said, I think it controlled really well and I appreciated the detail in the level-up info. Definitely a cool base for a roguelike or arcade experience here if you kept fleshing it out. I think you should feel great about this for a first GMTK submission!