First off, the game looks amazing! I love the character designs, and the art is polished and well done throughout! The songs are all great picks, and work well.
I like rhythm games in theory, but I'm not terribly good at them. I did manage to make it through the full game though! My experience ranged from moments of really feeling in the grove, to frustrating strings of missed beats. All and all, the gameplay felt solid, but maybe a little more leeway or visual cue to help less rhythm skilled players like me. (I did get A ranks on several levels though, so I guess I wasn't that bad!)
One issue I ran into was a weird bug that almost stopped me from playing at all... I had the problem with no music when the level loaded up. I heard refreshing might help, so I did... and then not only was the music missing, but the character was invisible on the map! New games, continue, same result. All key presses generated "ok"s in this silent, invisible mode. This happened in Chrome and Firefox. The Ctrl + F5 suggestion didn't work on Firefox, but seemed to work on Chrome. At least, I finally got it to run correctly there.. I didn't push any further to see if it would glitch from further refreshing.
Anyhow, odd bug aside, really great entry!