The next zone consists only of a series of three bosses, two of them from classic Sonic games.
X-Zone[edit]
It seems that Eggman hasn't learned from his mistakes; the first boss is exactly the same as the first boss of Sonic the Hedgehog. Eggman hovers from left to right in his usual Eggmobile, bringing out a deadly sphere and swinging it around from the bottom of the vehicle in an attempt to harm the heroes. Use the floating platforms on the left and the right to help you out here; avoid the ball by jumping through the chain. Get enough hits on him and he'll flee to his next vehicle. Here you'll be going against the exact same setup as the first boss from Sonic the Hedgehog 2. Even easier then the last, Eggman simply cruises around the screen in a car which happens to be headed by a drill. Jump over him when he gets close, attack, and repeat. Soon enough, the second part of the battle will be over and Eggman will flee to his third and final vehicle.
You'll now be introduced to Eggman's latest invention, the Egg X. He has some rotating attacks, but the biggest danger here is his extending hand. He'll always target you and reach; if he grabs you, then expect to lose a great deal of rings. However, even this boss can be defeated with an easy strategy; whichever end of the screen Eggman is on, run to the opposite end and wait for his big reach. Stay in one place until the hand comes for you, at which point you can jump over it and attack Eggman.
The Moon[edit]
If you happened to be playing as Sonic the entire time (after having beaten the game using all four playable characters, of course) and managed to collect all seven Chaos Emeralds, then you're in for a treat. While X-Zone would have been the final act otherwise, you'll now be faced with a secret boss battle which leads to a good ending. You'll take control of Super Sonic as he flies through space, ready to take down Eggman once and for all. As always, Sonic's ring supply is slowly depleted while in super form; defeat the new mech quickly by dashing into its weak spot, the head. The robot will use its arms commonly here, whether to swipe at the flying hedgehog or guard its weak spot; even without a steady ring count, doing so shouldn't be too much of a challenge. Beat him in the time limit with eight hits for the grand prize.
After the battle, Sonic falls back to Earth, and is rescued in the nick of time by Tails and the Tornado. Thanks to the efforts of Amy, Knuckles, Tails, and Sonic, the world is once again returned to peace. See you next game!