In Sonic the Hedgehog 4: Episode 1 for the PS3, Xbox 360, Wii, and iPhone/iPad, you can unlock an alternate ending and a short preview of Sonic the Hedgehog 4: Episode 2.
To do this, you’ll need to collect all seven Chaos Emeralds in the game. Once you have all seven, beat the game to unlock the alternate ending and watch the preview of Episode 2.
