I tried to play it a couple times, but unfortunately it crashes for me every time (Windows 10). Once I managed to get to wave 2, but mostly on wave 1.
From what I managed to play, I really like the idea. Extra damage on beat is nice mechanic. Maybe I'd increse damage dealt on beat to 4-5. Going from 2 to 3 seems to not be significant enough given that I can just spam attacks and have higher DPS that way. I did not manage to use adrenaline rush because of the crashes unfortunately.
I assume you would like to have the hand rotate not around itself, but around a point at some distance? You can do this very easily if instead of rotating the hand itself you add it as a child of Position2D, move the hand on X axis (say 10 px) and rotate Position2D.