A very fun an entertaining rhythm game. The different styles of game play and visuals make it pleasing to the eye and almost feel like an entirely different game. I did not have a problem with difficulty, I was able to 90%+ every song (except for one where I had to click the circles as they appeared because I played on a laptop. It was nightmarish.)
It was interesting when I played the free mode and a "bonus song" appeared where you played notes on the robots legs. I thought that feature was neat, but I think that you could change that somehow. For example, maybe change it so that when you find the song, you can play it again in the main menu. Or just have all the songs available. Although, the way it is now makes it great for replay value.
Overall a very good game!