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