Enter these at the bottom of the screen to advance further in Blue Sphere:
3659 8960 3263: Level 1
2965 3192 9023: Level 2
3610 2354 7327: Level 3
2921 0274 3999: Level 4
3737 7423 1487: Level 5
3053 9029 9071: Level 6
2340 2318 5760: Secret Level

Easy
Red, Red, Red, Has Bean: 2
Clear, Purple, Clear, Green: 3
Red, Clear, Has Bean, Yellow: 4
Clear, Blue, Blue, Purple: 5
Clear, Red, Clear, Purple: 6
Purple, Yellow, Red, Blue: 7
Yellow, Green, Has Bean, Blue: 8
Yellow, Purple, Has Bean, Blue: 9
Red, Yellow, Clear, Has Bean: 10
Green, Purple, Blue, Clear: 11
Red, Has Bean, Has Bean, Yellow: 12
Yellow, Has Bean, Blue, Blue: 13

Normal
Has Bean, Red, Yellow, Clear: 10
Clear, Red, Red, Blue: 11
Green, Green, Clear, Yellow: 12
Purple, Yellow, Has Bean, Clear: 13
Has Bean, Clear, Yellow, Yellow: 2
Blue, Clear, Red, Yellow: 3
Yellow, Blue, Clear, Purple: 4
Has Bean, Green, Blue, Yellow: 5
Green, Purple, Purple, Yellow: 6
Purple, Blue, Green, Has Bean: 7
Green, Has Bean, Clear, Yellow: 8
Blue, Purple, Has Bean, Has Bean: 9

Hard
Green, Clear, Yellow, Yellow : 2
Yellow, Clear, Purple, Clear: 3
Blue, Green, Clear, Blue: 4
Red, Purple, Green, Green: 5
Yellow, Yellow, Clear, Green: 6
Purple, Clear, Blue, Blue: 7
Clear, Yellow, Has Bean, Yellow: 8
Purple, Blue, Blue, Green: 9
Clear, Green, Red, Yellow: 10
Blue, Yellow, Yellow, Has Bean: 11
Green, Clear, Clear, Blue: 12
Has Bean, Clear, Purple, Has Bean: 13

Hardest
Blue, Blue, Green, Yellow: 2
Green, Yellow, Green, Clear: 3
Purple, Purple, Red, Has Bean: 4
Green, Red, Purple, Blue: 5
Blue, Purple, Green, Yellow: 6
Blue, Purple, Green, Has Bean: 7
Clear, Purple, Has Bean, Yellow: 8
Purple, Green, Has Bean, Clear: 9
Green, Blue, Yellow, Has Bean: 10
Green, Purple, Has Bean, Red: 11
Red, Green, Has Bean, Blue: 12
Red, Red, Clear, Yellow: 13

XXXXXX: Cancel all codes
MUSEUM: Fight only bosses
ILOVEU: Level select
MIEMIE: See hidden items
SUPER: Super hard mode
DOFEEL: Time attack
MAGURO: Tone deaf sounds
SUPERB: Very hard difficulty

Debug Mode
To enter Debug Mode, play these sounds from the level select screen: 1, 9, 9, 2, 1, 1, 2, 4. Press Start and hold A. To start debugging, press B, then you can select any sprite in that level and put it on the screen. To select a different sprite, press A, and to place it on the screen, press C. Note that sprite selection is different from Zone to Zone. Also, instead of displaying the time elapsed, it displays the number of sprites currently on the screen.

Level Select
From the main screen, select Options. Select Sound Select and play sounds 19, 65, 9, 17, then push C. Press Start to return to the main screen, and when Sonic and Tails appear, hold A and press Start.

Sonic 2

Level Select: At the main menu press UP, UP, UP, DOWN, DOWN, DOWN, LEFT, RIGHT, LEFT, RIGHT. Hold X and press START to access level select menu.

Debug Mode:Go to the sound test from the level select menu and play these tracks in order: 01, 09, 09, 04, 01, 00, 01, 08. This enables Debug mode. Holding X when selecting a level swaps objects from the level with the A button. Change objects with the B button, and copy and object with the X button. To reset the game, pause and press X.

All Emeralds: Play tracks in this order: 01, 06, 07, 07, 07, 02, 01, 06. To get all of the chaos emeralds.

Sonic 3 and Sonic and Knuckles

On Angel Island jump on the swinging vine near the bonus stage. While swinging press LEFT, LEFT, LEFT, RIGHT, RIGHT, RIGHT, UP, UP, UP. You should hear a ring chime. Sound Test will appear under the main menu.

Select Mushroom Hill Zone until you reach the ratchet machine. Hang from the machine and press LEFT, LEFT, LEFT, RIGHT, RIGHT, RIGHT, UP, UP, UP. Pause and press X again to reset. In level select , choose any level while holding X to use debug mode. Holding X when selecting a level swaps objects from the level with the A button. Change objects with the B button, and copy and object with the X button. To reset the game, pause and press X.

• UP, B, DOWN, B, LEFT, B, RIGHT, B and hold X when starting a level to get Debug Mode
• UP, DOWN, LEFT, RIGHT press X + START to get the Stage Select Screen

• The Ooze: Unlock all games with exception to Ristar.
• Comix Zone: Scroll down the list of Genesis-only games (including unlockables) and play them each 20x.

Keep each game open for three hours to unlock hints. Hints are available under the options menu.

• Blue Sphere game
  Play Sonic the Hedgehog and Sonic 3D Blast 20 times each, exit to the title screen and then go back into the game select screen and Blue Sphere will now be unlocked.
• Flicky
  Play Mean Bean Machine 30 times and Flicky will be unlocked.
• The Ooze
  Have a Sonic Heroes save on the Xbox.
• Comix Zone
  Have a Sonic Heroes save on the Xbox.

Play Sonic the Hedgehog 2 and Sonic Spinball 20 times each.

Play Blue Sphere, Knuckles in Sonic 2, Sonic 3 & Knuckles, and Flicky 30 times each.

Play Sonic 3 and Sonic & Knuckles 20 times each.