I love the idea! I like how you managed to combine art with the goofy horde survival genre. The artwork is nice and cute, and the mechanics are pretty well thought-out. Some of the balance and mechanics are a little rough around the edges, and a little tough to figure out, but it's a jam game, so who cares if it's imperfect.
The only other thing I'd like to note, however, is that the music in the background could use some variety. I love the song, and once all of the instruments come in, I think it's an absolute banger, but when it's just the first part, it feels like it's just the same few notes repeating for a good 20 or 30 seconds. My suggestion (whether you choose to update this game or make more games going forward) is to just take your main instrument, and for every other measure, just move each note up or down by 1 note. This can do wonders for making your music nicer to listen to and less repetitive. This is a just a suggestion though, and I am not very well educated in music (self taught solo dev moment), so take my advice with a grain of salt.
Overall, I enjoyed the game, I think your idea is super unique, and I think it's executed quite well :)