This is one of those games that doesn't live up to it's lifetime.
The graphics are powerful and incredible, but it gets pretty boring to look at later on. The sound isn't that glamorious, because of the fact you will notice the sound is broken. The camera was not that pleasant. It's off of target every angle. The controls don't live on. It's hard to control the characters, espicially Super Sonic. The game-play is not very inspering. Robotnik is the main enemy, yet he is a playable character.
But, the most notable thing is the music. There are vocals almost everywhere. You can take the vocals off with the option, but that's worthless anyways. Who would want to listen to music that has vocals and singers in it when you could hear only the music just like every game before it. This would be included in Sonic Adventure, but that was the perfect time. This, however, is not. Other than the vocals, the music was okay, I guess.
This game is good enough to be a cult game. But it's not good enough to become a worldwide phenominom. Rent it online, and when you're done, give it back and go on with you're life. It's fun when you first get it, but when you play it a lot, it doesn't get into you.