When you have control of Ecco and can pause, Try to pause while Ecco is facing you. Once Ecco is facing you, press A, B, C, B, C, A, C, A, and B. If you entered the code correctly, a menu will pop up with all sorts of optionssuch as a sound test, level select, tempo, etc. This code can be entered as many times as you'd like, as long as the game is paused while Ecco is facing you.
Hard Mode
In the starting area break the two shells above you, and then swim through the tunnel to start the game in hard mode.
Level Passwords
Crystal Springs = UEPMCVEB
Fault Zone = OZUNSKZA
Two Tides = KDKINTYA
Skyway = SZXHCLDB
Sky Tides = OZWIDLDB
Tube of Medusa = QSJRYHZA
Skylands = MULXRXEB
Fin To Feather = YCPAWEXA
Eagle's Bay = YCJPDNDB
Asterite's Cave = AOJRDZWA
Four Islands = UOYURFDB
Sea of Darkness = UQZWIIAB
Vents of Medusa = MMVSOPBB
Gateway = KDCGTAHB
Big Water = QQCQRDRA
Deep Ridge = UXQWJIZD
Hungry Ones = WBQHMIUE
Secret Cave = CHGTEYZE
Gravitorbox = UIXBGWXE
Globe Holder = SBFPWWJE
Dark Sea = MXURVMLA
Vortex Queen = OKIMTBPA
Home Bay = CSNCMRUA
Epilogue = CEWSXKPA
Fish City = SGTDYSPA
City of Forever = WSSXZKVA
Passwords for Hard Mode
Crystal Springs: WPHSAAFB
Fault Zone: CRNPTFZA
Two Tides: QUKGZZYA
Skyway: MCMBPJDB
Sky Tides: OZMRKIDB
Tube of Medusa: ODFADPYA
(@) Aqua Tubeway: KNHRKJYA
Skylands: WXRDJYEB
Fin to Feather: UQTFBRXA
Eagle's Bay: QSNVMMDB
Asterite's Cave: EGAQRVXA
(@) Maze of Stone: EUTQQQWA
Four Islands: CZVQNHCB
Sea of Darkness: WFMYIDAB
Vents of Medusa: SHWZZNBB
Gateway: QKLLFPHB
Moray Abyss: YCFSBRAB
The Eye: AGNEXBTE
Big Water: YCBXONIA
Deep Ridge: UPODMUQD
The Hungry Ones: YOHVUVLE
Secret Cave: SPKHKISE
Lunar Bay: WTHXKISE
Black Clouds: USKIKDOE
GraviatorBox: WNQWZMME
Globe Holder: MIPGDOME
(@) New Machine: GOSTCXJA
Vortex Queen: OOSFBXAA
Home Bay: QNSGAPGA
Epilogue: AXBGKHBA
Fish City: WKGETHCA
City of Forever: WQHFTZHA
''Secret'' Password: AVQJTCBA
@ = New level found only in Hard Mode
Unlimited Air and Health
Turn Ecco left or right and pause the game while Ecco is facing towards the screen. Press (A), (B), RIGHT, (A), (C), (A), DOWN, (A), (B), RIGHT, (A), and then unpause. You will now never die from lack of air or injuries.
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