It was good, and I liked the music and how it synced up, but the gameplay by itself wasn't much to write home about. I have the vague sensation that I've been tricked into listening to a song I wouldn't otherwise have.
It's quite easy, and I think making the main challenge not survival or success but just getting a good score - while being necessary to make first-time players hear the whole song - kind of sucks, and it betrays what the main focus of the game is. Advertising, I guess. Still, good ad?