This one's freaking AWESOME. I'll admit, I was expecting more Vampire Survivor-style games this jam than I've actually seen, but this one is my new favorite of the ones I've played.
Honestly, everything about this is so polished and high-quality. The art is fantastic, the controls are tight, the gameplay loop is satisfying (if a little bare-bones, which is completely understandable for a game jam).
I hate to say anything negative about the sounds since the sound design is actually another huge strong point, but I'll admit I don't love that "clicking" or "snapping" sound that seems to be tied to every single impact hit. EQ the higher frequencies of that sound down and then I'm fully in love with the sound design.
In terms of game design, I would let people by as many upgrades as they want in one wave, at least when the upgrades are this limited. But I LOVE the death screen, that eye that pops up and looks around while you're upgrading, all of it, I love it! This game has a cool identity, and I think you could really flesh out the world with a sweet story if you wanted to.
Fantastic job!!!