Sonic the Hedgehog 4 Episode 2

Have a saved game file from Sonic The Hedgehog 4: Episode 1, then complete Sylvania Castle Zone Act 1. Go to the "Map" screen and you can now play as Metal Sonic in Episode Metal.

When you complete each of the special stages and obtain ALL 7 Chaos Emeralds Super Sonic will become available as a playable character. Note: You must collect 50 rings in a given stage.