Other than the crappy plot (Aliens, really?) forgettable music, boring levels and crapping On Gerald Robotnik's character.
The game is deadset on choices. Who will I side with? So with this, why isn't there a single ending where I can side with Eggman?
Even if the mission before that I purposely help out the doctor? I don't want to side with Black doom. Why should I care about him, I wanna side with Robotnik!