Sonic Colors: Ultimate

Chaos Emeralds are obtained through the Game Land area by completing unlocked levels. Levels become unlocked by collecting Red Star Rings found throughout the game. When you find enough, you will be notified that you have unlocked some new levels in Game Land. When you go into Game Land with all levels unlocked, you will see that there are 7 Chaos Emeralds with 3 levels under each one. You must complete all 3 levels in order to obtain the corresponding Chaos Emerald. Once you have collected all 7 Chaos Emeralds, you will unlock the ability to transform into Super Sonic.