Easy rings for Black Market:
After obtaining the Light Shoes (and Crystal Ring to speed up the process), go to the Casino area and step on the button to make the rings appear. You can do this repeatedly for more starting rings. Note: The ring limit can exceed 999, but you cannot tell exactly how many you have. Listen for the extra life sound to keep track of them. When you are satisfied, go to Emerald Coast and complete the level without getting hit. You will be awarded with however many rings you collected at the end. Go to the Chao Garden, then the Black Market, and spend your hard earned coins.
Unlockable Characters:
Unlock the following characters by performing the corresponding tasks:
CHARACTER – HOW TO UNLOCK
Amy – Talk to her in the Casino as Sonic after finishing Sky Chase.
Big – Defeat Chaos 6 as Sonic.
E-102 Gamma – Defeat Gamma after finishing Sky Deck as Sonic or Tails. An alternate way to unlock him is to finish Twinkle Park as Amy and watch the FMAs after it.
Knuckles – Defeat him after finishing Ice cap as Sonic or Tails.
Miles Tails Prower – Finish the C mission of Emerald Coast action stage as Sonic.
Play Emerald Course in chao race – Beat the rest of the four courses. Note: Don’t delete your your chao data or else you will have to do them again.
Super Sonic – Successfully complete the game with all characters.
Metal Sonic (Sonic Adventure: DX):
To unlock Metal Sonic, collect 130 Emblems, then select Trial mode and choose Action Stage.
Play Emerald Course in Chao race:
To play the Emerald Course in Chao race, beat the other four courses.
Playstation Home items:
Unlock the following items in Playstation Home by performing the corresponding tasks:
ITEM – HOW TO UNLOCK
Light-Speed Shoes – Unlock the light-speed shoes in-game, then re-load the game and saved game file.
Sonic Adventure T-Shirt – Clear all character’s stories.
Trophies:
Bronze trophies
Miles ‘Tails’ Prower – Become friends with Tails.
Knuckles the Echidna – Become friends with Knuckles.
Amy Rose – Become friends with Amy.
E-102 ‘y’ – Become friends with E-102.
Big the Cat – Become friends with Big.
Sonic the Hedgehog – Clear the Sonic story.
Super Sonic – Clear all characters stories.
Metal Sonic – Get all 130 Emblems by playing Sonic Adventure DX.
Silver trophies
The Fastest