Genuinely, just wow. The art is amazing, it's fun to play and I genuinely hope you will make this into a longer game, because I would definitely play that!! I think the balancing is good as in, I got to the end but it didn't feel like there was a lot of choice with the upgrades (not a bad thing, simply can't make 100+ levels in a game jam) :)
Rated the game and will put another comment on the rating page, but genuinely, the fact you worked hard on it is clearly visible!