Sonic 4 – Super Sonic Is Here!
The latest screenshot floating around of Sonic the Hedgehog 4 confirms that YES, Super Sonic will be in the game. Not only that, but it appears that you will be able to use him in any stage just like the good old days! That alone is a step in the right direction for Sonic 4. Apparently, by clearing all stages as Super Sonic will grant you the Golden Flash achievement in the game.