It's a fun novelty game and probably something that's fun to play with a friend but as a fighting game it's pretty meh it's clear they focused more on the style and soundtrack of the game which in this case isn't a bad thing since I love it's art style.
I wish there was a bit more to its rhythm game within in a fighting game gimmick that's an idea that has a lot of untapped potential and they don't do much without here, your level 3 supers are just a mini rhythm games that will give you a small cutscene if you use it when your opponent is near death but sometimes they can interrupt the flow of your super by adding their own notes during your super which serves as a small challenge but it's pretty easy to avoid.
If this game wasn't Japan exclusive and it's battle system got some refinements I'd like it as a whole but it's more of a eye candy game.