Guilty Gear X
Get to level 20 in survival mode and Testament will appear and challenge you.
Defeat Testament to unlock him as a selectable character.
Get to level 30 in survival mode and Dizzy will appear and challenge you. Defeat
Dizzy to unlock her as a selectable character.
Guilty Gear mode:
Get to level 100 in survival mode or successfully complete the game using every
Highlight a fighter at the character selection screen. Press Start, Select, or
A + X, or B + Y for more costume colors.
Successfully complete arcade mode to unlock the corresponding character's ending