How to Unlock Everything in Sonic Advance 2

Unlock the characters Tails, Knuckles and Cream. Unlocking characters provides you with the option to play the game as them. To unlock Tails, complete the Music Plant level as Sonic, and for Knuckles complete the Sky Canyon level, also as Sonic. Unlocking the rabbit, Cream, involves beating the Leaf Forest level with Sonic.

Unlock the character Amy. To unlock Amy, you must beat the game with Sonic, Cream, Tails and Knuckles, as well as acquire all 7 Chaos Emeralds, which can be obtained in the bonus stage at the end of each level. To enter the bonus stage, you must collect 7 "Special Rings," which look different than normal ones, throughout the course of each level, without dying.

Unlock the special features. The Tiny Chaos Garden is a bonus area that allows you to level up and "grow" different Chaos sub-characters. To unlock this, simply defeat the game with all 7 Chaos Emeralds using any character. To access the sound test option, defeat the game with any 2 characters and obtaining the 7 Chaos Emeralds. More sounds are added after defeating the extra level with Sonic. To unlock the "Boss" option in the time attack mode, you must defeat the game with 3 characters, while acquiring the 7 Chaos Emeralds.

Unlock the extra level. Defeating the game with Sonic, Tails, Amy, Knuckles and Cream in addition to collecting all 7 Chaos Emeralds will unlock the bonus level, which can be accessed at the very edge of the map screen.