The attacking jump interrupt was an on-purpose/intentional thing, though I think I’d cut interrupt time in half going forward.
I didn’t get many opportunities for feedback on the final boss, thanks for writing up some feedback on it!
The music not playing in the upper section is definitely a bug. I think I might need to switch out the music manager I used, I’ve had a lot of reports of music problems with this one, and enemies being able to hurt you while dying was definitely something I should have addressed.