Hi!
Very solid entry! Polished, fun, good looking, and I definitely was headbanging while playing!
I also really like that the game has a 5 waves system, which makes it shorter than survivor-likes games and fits a jam entry well.
The fact that money disappears at the end of each wave was a bit frustrating at first (as that does not happen in most survivor-likes, at least not the ones I've played) but is an interesting touch and invited me to play again and try to collect more before wave ends.
And I wish there was a way of healing up between waves (maybe there is and I did not see it though), for instance a cassette giving a few HP, that would be a tradeoff as you sacrifice damage on a beat to survive a bit longer.
Anyway, tbh there are not many negative points, overall the game is very cool! :) and an impressive amount of work even for a 4 days game jam.
Congratulations!