Guilty Gear X

Fight as Dizzy or Testament:
Press Down, Right(2), Up, Start at the ''Press Start Button'' screen. A Japanese phrase will be spoken at the main menu to confirm correct code entry. Dizzy and Testament will be unlocked as playable characters in any mode.

Testament:
Get to level 20 in survival mode and Testament will appear and challenge you. Defeat Testament to unlock him as a selectable character.
Information in this section was contributed by Flame on56.

Dizzy:
Get to level 30 in survival mode and Dizzy will appear and challenge you. Defeat Dizzy to unlock her as a selectable character.
Information in this section was contributed by Flame on56.

Guilty Gear mode:
Get to level 100 in survival mode or successfully complete the game using every character.
Information in this section was contributed by Flame on56.

Alternate costumes:
Highlight a fighter at the character selection screen. Press Start, Select, or A + X, or B + Y for more costume colors.

Stage select:
Highlight any fighter at the character selection screen, then press L.

Ending sequences:
Successfully complete arcade mode to unlock the corresponding character's ending sequence.

Soundtrack:
Place the small bonus disc in an audio CD player that features a tray capable of playing a CD single disc. Play track two and above to hear music from the game.

Hidden artwork:
Place the small bonus disc in a PC compatible CD-ROM that features a tray capable of playing a CD single disc. Two images from the game can be found in the "extra" folder.