Collect a Chaos Emerald.
Earn a Continue in either a Bonus or Special Stage.
Enter a Bonus or Special Stage.
Start the game once as each character.
Complete the game as Sonic.
Collect 100 rings.
Complete the game as Knuckles.
Collect all seven Chaos Emeralds.
Finish the Lava Reef Zone.
Finish the Sandopolis Zone.
Finish the Flying Battery Zone.
Finish the Mushroom Hill Zone.