Get Femme Fatale:

To get Femme Fatale, win eight matches in a row on the arcade mode.

Get Ice-T:

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

Get Mask:

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

Unlock Bruce Buffer:

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

Unlock John McCarthy:

Beat UFC mode using Bruce Buffer to unlock John McCarthy.

Unlock Mario Yamasaki:

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

Unlock The Cat:

To unlock The Cat, win four matches in a row on the arcade mode.