I really like the idea - Necrodancer and Battle Network are some of my favorite games of all time, and this is a great way to combine the two. The art looks great and the music is a bop, too.
I found it kind of hard to tell if I was actually playing on beat. I think it would help if you game could tell you where it thought you hit within the beat, and latency calibration would also be nice. Both of those probably take too long to implement for a game jam, though, so I understand why they aren’t in the game.