Pretty good!
Was pretty good for a game made in a short time frame however do you plan to release an updated better version cause heres a few things you could add:
-Effects when you time the arrow presses right
-moving backgrounds or atleast some form of movement/animation besides just the character
-more characters
-difficulties
-More songs (obviously)
-Some kind of indication that you've missed a note eg. a sound or the music goes quieter
-some form of special power up mode (or something to that effect)
-more headbang animations (eg. from down to up theres an animation of them flicking up to it )
I know I've said a lot but it would make this game tons more fun and you would get a lot higher ratings :)
Score: 6/10 3/5