Bruce Buffer:
Win the Silver and Gold belts with all middleweight fighters.

Card girl:
Win the Silver belts with all of the default fighters.

Dana White:
Win the Silver and Gold belts with all lightweight fighters.

Lorenzo Fertitta:
Win the Silver and Gold belts with all welterweight fighters.

Mario Yamasaki:
Win the Silver and Gold belts with all light heavyweight fighters.

Unlock John McCarthy:
Win the Silver and Gold belts with all heavyweight fighters.

Kung-Fu fighting style:
Successfully complete career mode with a kick boxer.

Karate fighting style:
Successfully complete career mode with a created Sumo fighter.

Nin-Jitsu fighting style:
Successfully complete career mode with a karate fighter.

Silver belt:
Complete UFC mode with a default or created character to win the Silver belt.

Gold belt:
Win the Silver belt with a character, then enter UFC mode. Select the Free Weight option, then select the character with the Silver belt. Complete UFC mode again to win the Gold belt.

Bonus moves:
Accomplish one of the following tasks to unlock another move:

Complete UFC mode and get the Silver belt.
Complete UFC mode in the Open Weight class and get the Gold belt.
Complete the game in Arcade mode.
Complete the game in Tournament mode.