This game is awesome!
Having the game be waved-based with choosing your upgrades really elevates it so much! It was super enjoyable having certain builds on each run and seeing how they play.
There isn't much criticism I can give, it's very polished and I love the art! It would help to have audio or visual feedback from being hit, and I would love to see a score screen once you lose, but that doesn't take away from the experience at all and it's so fun!