Great concept and presentation but this game is killed by several fatal flaws:
1.) It's too damned easy. Hitting a key when there is nothing there does not penalize you in any way, so you can just button mash the entire time.
2.) If losing is possible, I haven't found out how. There's no crowd to boo you off stage if you fuck up.
3.) The gameplay is really stale without a star power mechanic. It's just hitting the same notes with no reward other than getting that little (useless) number in the top right up.
4.) The characters are drawn really well and their idle animations are nice to look at, but when you hit keys they suddenly start spazzing out. The directional animations are really choppy and distracting. It just looks ugly.
5.) Way too many sections that require "Hit up/down over and over" or "hit the keys counter-clockwise". Even "hit the keys in the shape of a lying eight". Hit directional keys in the shape of a lying fucking eight? That a joke? These sections are straining on the fingers, boring, too long, and some songs use them for 90% of the play time.
To be fair, the game does have some good to it. The presentation and artwork are nice. The characters are very well drawn, and the music is good. The gameplay itself is core here though, and it just has way too many flaws for me to recommend.
Verdict: 5/10, 2/5.