Coming from it's vid, and it looks super neat, but I feel like it needs work. Little things. Maybe a formal tutorial for the violin playing. Maybe more than just sparkles on the spikes; maybe just make them a more prevalent, brighter color... or go full 'red = dead' on them.
And while you can go all desaturated on the looks, the style, to me, doesn't seem to fit the gameplay. But this is hours and hours of Hollow Knight talking, so grain of salt on the last one. Muscle memory + visuals are very much kicking in, I think.