For the following code to work you must first enable ABC mode in 'Controller Setup'. The two sound test areas are at the 'Options' and 'Level Select' Screen.

Level Select:
19, 65, 09, 17. When you hear a Ring noise go to the 'Title' screen. Then hold A and press 'Start'.

Super Sonic:
04, 01, 02, 06. When you hear an Emerald noise hold A and Press 'Start' on a stage at the 'Level Select' screen and you will have ALL Emeralds.

Debug Mode:
01 ,09, 09, 02, 01, 01, 02, 04. When you hear a Ring noise hold A and Press 'Start' on Stage at the 'Level Select' screen.

Ecco The Dolphin

Unlock Unlimited Air:
Enter the code 'LIFEFISH' without the quotes.

Unlock Unlimited Lives:
Enter the code 'NIHPLODS' without the quotes.

Level Passwords
Enter the following passwords to unlock the corresponding level.

Unlock Island Zone:
Enter PLEASEFF

Unlock Last Fight:
Enter PLEASEOO

Unlock Marble Sea:
Enter PLEASEUU

Unlock Open Ocean:
Enter PLEASEWW

Unlock Origin Beach:
Enter PLEASEQQ

Unlock Deep City:
Enter PLEASEKK

Unlock Ice Zone:
Enter PLEASEEE

Unlock Pteranadon Pond:
Enter PLEASEGG

Unlock City of Forever:
Enter PLEASEHH

Unlock Under Caves:
Enter PLEASEII

Unlock Ridge Water:
Enter PLEASEZZ


Altered Beast

Unlockables
Enter the following codes at the 'Title' screen to unlock the corresponding effect.

Unlock Options Menu:
At the 'Title' screen hold X and push 'Start'.

Unlock Level Select:
Enable the 'Options' menu and select a level. Then hold square and press 'Start'.

Continue Game on Last Level:
When you die hold 'Square' and repeatedly press 'Start'.

Select Beasts for Levels:
At the 'Title' screen hold Square, X, Cirlce, Down/Left and 'Start'.

Unlock Sound Test:
At the 'Title' screen Hold Square, Circle, Up/Right and 'Start'.


Sonic the Hedgehog

Unlock Level Select:
Press Up, Down, Left, Right then hold X and press 'Start'.

When you have a 'Game Over' go to the 'Title' screen and then 'Options' and press 'Continue' and you will be returned to the stage that you died in.

At the Main menu go to Jukebox and select 3, 12, 17, 2, 2, 10, 2, 7, 7, 11 in the that order. If the code has been entered correctly you will hear a voice say 'Oh Yeah' as confirmation and you will now have unlimited health during the game although falling into pits will still kill you.