The game itself is nice, love Calli's music. Love the look and style and the animations are nice.
HOWEVER; it is NEEDLESSLY DIFFICULT. I'm going to be the more critical reviewer and say what needs to be said, whether it feels mean or not. Go ahead and downvote me.
You definitely didn't cater this to her average fans but only to some extreme, die-hard players. I can promise you that over 95% of players won't be able to get through without having to turn on the Apprentice option to avoid dying, and I am an avid lover of rhythm games.
All of the obstacles have to be avoided OFF BEAT, which goes against the instincts of every rhythm gamer. You can't see anywhere near enough of the track to be able to avoid everything coming your way, guaranteeing that you die unless you invest a LOT of time into learning each track. It also doesn't help that the input feels rather slow. Combined with the off-beat dodging and having to jump 3 spaces in a single beat sometimes and having to hit pink obstacles all the while, it makes for a very frustrating experience.
Love the idea, but you made this too frustrating for the majority of people to enjoy, so it ends up leaving them with a rather sour experience. It has the potential to be great, but as it is right now, it has to be reworked if you want a lot of people to enjoy it. You know there's a tad of a problem when most of the comments are in regards to the difficultly of the game play.