Very fun game! Combat is interesting and fresh, the aztec/mushroom fight was an amazing trip. Very nice music as well!
The club is kind of barren, could do with some set dressing. In fact, most of the areas could do with some side visuals or more puzzles, as its a bit disappointing to just run through black areas just following a path.
Likely due to it being a demo, but the combat ramps up a bit to quickly. You went into final boss visuals for the fourth fight in the game during Act 1. Could tone it down for the final release.
(not really criticism) The fights are amazing, but I worry that it might be hard to make an entire game with fights these complex and unique. Most games have some sort of trash mob, but every fight in this game is the equivalent of a boss fight. Makes for very memorable encounters, but I worry that the pacing/length will suffer.
The music box puzzle sound positioning is a bit odd. I spent around 5 minutes feeling around in the dark for something because you could narrow down the source of the music, but I didn't find anything. Maybe the music source could be changed to a strip of area instead of a point, or some interactive object could be placed at the music source.
Kind of a nitpick, but the combat feels a tiny bit cramped. The notes start a tiny bit too close to plan in my opinion. Could leave it as is if you are going for that style though.
In conclusion, I will be following this game to see where it goes, and am eagerly looking forward to the full release! Amazing work so far!