Bruce Buffer
To unlock Bruce Buffer, beat UFC mode with every fighter.

John McCarthy
Beat UFC mode using Bruce Buffer to unlock John McCarthy.

Mario Yamasaki
To unlock Mario Yamasaki, beat the UFC mode using John McCarthy.

The Cat
To unlock The Cat, win four matches in a row in the arcade mode.
Femme Fatale
To get Femme Fatale, win eight matches in a row in the arcade mode.

Ice-T
To get Ice-T, win sixteen matches in a row in the arcade mode.

Mask
To get Mask, win twenty seven matches in a row in the arcade mode.