@AlexHallon - If you're good at music games, I'd say that the only really challenging part is 1) Unlocking all the songs, and 2) Beating Seven Circles with 95%+ on Crazy. Everything else can be practiced through.
I liked it, but it is still very simple. The concept would be good with some refining to the system.
The music was very very nice, in my opinion. The mute button is also helpful for when you get tired of it.
I actually REALLY don't like this game, which is rare for me. I love games. Games are the best. This however is just cumbersome and time-consuming with no sense of reward except the slow painful slaughter through levels in hopes of getting to Level 20 so you don't have to waste any more time on this game.
 "Auto-Attack!"){kind=icon}
 "DJManiax"){kind=icon}
 "Bactoggle"){kind=icon}
 "oO"){kind=icon}
 "sdfsdfsdf"){kind=icon}
 "Gardevoir Hunter"){kind=icon}
 "Ninja Hamsters vs Robots"){kind=icon}
 "Don't Touch the Tangerine"){kind=icon}
 "Amorphous+"){kind=icon}
 "Idle Dancing"){kind=icon}
 "You Only Live Once"){kind=icon}
 "Insanity Box 2"){kind=icon}
 "The Insanity Box"){kind=icon}
 "Space is Key 2"){kind=icon}
 "Effing Meteors"){kind=icon}
 "The Love Letter"){kind=icon}
 "Music Bounce"){kind=icon}
 "Learn to Fly 2"){kind=icon}
 "Clarence's Big Chance"){kind=icon}
 "Multitask 2"){kind=icon}
Thank you for your comments and time! I just added some new awesome tracks, and there is a surprise when you bounce on a green Sphere ;). Greetings