The Ultimate 2D Sonic Adventure!
It has been quite a while since anyone has heard from Dr. Robotnik after his previous defeat. Until one day, Tails and Knuckles have gone missing! Sonic finds out that Robotnik discovered a new gem: the Paradigm Emerald. He has rebuilt the Death Egg with its extraordinary power, using Tails and Knuckles as living batteries to power it. Sonic rushes to save his friends, and most importantly, the world!