Unlock GameGear Games
Get a Sonic emblem or finish ten missions. The 'minigame' option will be added to the main menu.
Chao flying
To help your chao fly, give it a bird.
Chao Running
To help your chao run, give it a deer animal, a rabbit or a wallaby.
Chao strength
To increase your chao's strength, give it any of the following animals: elephant, gorilla, lion.
Chao swimming
To improve your chao's swimming ability, give it any of the following animals: seal, penguin, beaver.
Unlock Sonic Spinball
Collect 80 emblems.
Unlock Sonic Drift
Collect all 40 emblems.
Unlock Sonic
Collect all 20 emblems.
Sonic Chaos: Level select
Press Up(4), Right, Left, Right, Left, Start when "Press Start" appears at the Sonic Chaos title screen.
Sonic Labyrinth: Level select
Press Up(2), Right(3), Down(6), Left(9) when "Press Start Button" appears at the Sonic Labyrinth title screen.
Sonic Spinball: Level select
Enter the "Sound Test" option for Sonic Spinball. Then, play the following songs in order: 0, 2, 1, 5, 6, 6.
Sonic Spinball: Faster background music
Enter the "Sound Test" option for Sonic Spinball. Then, play the following songs in order: 0, 4, 2, 5, 5, 7.
Sonic Spinball: Disable gravity
Enter the "Sound Test" option for Sonic Spinball. Then, play the following songs in order: 0, 9, 0, 1, 6, 8.
Sonic Spinball: Zoomed in view
Enter the "Sound Test" option for Sonic Spinball. Then, play the following songs in order: 0, 2, 1, 1, 6, 6.
Sonic The Hedgehog 2: Level select
At the Sonic The Hedgehog 2 title screen, Tails will blink his eyes (first once, then two times quickly). While holding Down/Left + A + B, tap Start just when his eye shuts on the second blink of the double-blink.
Two player Game Gear mode
Press Start on controller two to display a second Game Gear screen for that player. If the original Game Gear game supported the multi-player link, the current game will switch to multi-player not. If the game did not support the multi-player link, game play on each screen will be unrelated.
Toggle Game Gear game screen
To view the Game Gear games in a smaller, not pixelated view, press L + R. Pressing L + R again will return the view back to normal.
In-game reset
Hold Start + A + B + X for a few seconds during game play.
Play as Super Sonic
Complete the game using all six starting characters to unlock Super Sonic. Sonic will transform into Super Sonic after some time into the next game.
Play As Metal Sonic
Collect all 130 Emblems to unlock Metal Sonic in trail mode.
Play as Tails
Controller two may be used for Tails after he is obtained during game play in story mode. Note: Shields, invincibility and extra life boxes have no effect on Tails if collected. Note: If Tails goes too far away from Sonic, he will appear next to Sonic.
Mission mode
Successfully complete the game in adventure mode with all characters to unlock the "Mission Mode" option at the main menu.
Glitch: Tails in Emerald Coast
As Tails, go to the pool outside the hotel. Go to the right 'till your directly below the balcony. Fly and do NOT move the anolog stick. You'll go through the balcony. Now slowly run outside of the hotel to a small platform. Note:This next part can be easier with the jet anklet. Now,try to fly over to the beach far enough so you won't die, and go to the blue gate. And you're in Emerald Coast. Note:You can only play the first part,then you'll back to the pool.
Extra Chao
To do this cheat, you must have Sonic Advance 1 or 2 and a Gamecube/GBA link cable.Go to the Chao Garden on Sonic DX, and step on the transporter. Then, turn on the Tiny Chao Garden on Gameboy Advance. Transport the chao you have in GBA to the Sonic DX garden. Then on GBA, go to the chao mini-store by pressing L. You will see a free egg. Buy it, hatch it, then transport it to Sonic DX. Keep on doing this until you have enough Chao.