This game is awesome, if you enjoy music.
If your goal would be just to beat every song then it would only take you a couple days or so to beat, but the whole fun of the game is to keep doing things until it is completely done which can give you hours and hours of fun.
It may not have the best song selection, but it still has great songs in it that you can play over and over again.
There's not much more to say, it's an awesome game that you will have to play sometime in your life.