I reached the 30th wave after I got the hang of the game.
This is impressive for a game made in 2 days, and you've made great use of the game jam theme. The game looks great and sounds great with the caveat that I'm specifically not fan of the metronome tick-tock, the rise in power is satisfying and the difficulty increases at an adequate rate.
Changing the controls is bugged, my impression is that what happens is that if I change a key then I change another all the previous keys I touched are all swapped to the new key instead of only the last one.
Thanks for sharing this game!