Wow, what a cool concept. I really like "Hades" and "Crypt of the Necrodancer", so this was a fun find for me. Finding where the beat fell was pretty difficult, and so sometimes I would just sit there until one of my inputs lined up and I could move/attack; after a few minutes I got better at it though. Also I was able to walk right past Cerberus for some reason.
I really liked the unique paper-cut-out look to the sprites, the music, and wholly cow, voice acting in a game jam game?! Great work.