Guilty Gear cheats and cheat codes for Playstation

Unlock Hard mode
Hold Down + Square + L1 + R2 and the power button on the PSX.
Keep the buttons held until the phrase "Team Neo Blood" disappears.
If the code is accepted, the "Normal Mode" will change to "Hard Mode"
and "Hard" will appear above the two chaos bar.

Unlock bosses: Testament, Justice, and Baiken (Japanese version)
Hold Down + Square + L1 + R2 buttons at the Arc System Works logo.
Then, release those buttons, when the message "Team Neo Blood"
disappears. Now you can play as the bosses in versus mode.

Change colors
Press Square, Triangle, Circle, or X at the character selection screen.

Guilty Gear Game Shark Codes:

Characters for Player 2
8013904C 0000 - Potemkin
8013904C 0001 - Zato-1
8013904C 0002 - Sol-Badguy
8013904C 0003 - Ky Kiske
8013904C 0004 - Chipp Zanuee
8013904C 0005 - May
8013904C 0006 - Axl Low
8013904C 0007 - Millia Rage
8013904C 0008 - Kliff Undersn
8013904C 0009 - Dr.Baldhead
8013904C 000A - Testament
8013904C 000B - Justice
8013904C 000C - Baiken

Character for player 1
80139048 0000 - Potemkin
80139048 0001 - Zato-1
80139048 0002 - Sol-Badguy
80139048 0003 - Ky Kiske
80139048 0004 - Chipp Zanuee
80139048 0005 - May
80139048 0006 - Axl Low
80139048 0007 - Millia Rage
80139048 0008 - Kliff Undersn
80139048 0009 - Dr.Baldhead
80139048 000A - Testament
80139048 000B - Justice
80139048 000C - Baiken

Unlimited Time
8007BF72 0000

Unlimited Health for player 2
8007CB68 00BC

Full Power for player 2
8007CB88 0040

Unlimited Health for player 1
8007CB98 00BC

Full Power for player 1
8007C8B8 0040