Here is the full list of all 39 UFC Undisputed 3 achievements worth 1,000 gamerscore.
Create a CAF and modify the face with CREATE A FIGHTER.
Win a match against the COM on Experienced Difficulty while using a CAF in Exhibition Mode.
Play 10 or more ranked Xbox LIVE matches.
Play 500 or more ranked Xbox LIVE matches.
Select a guided tutorial
Join an Xbox LIVE Fight Camp.
Enter the Hall of Fame with a fighter in Career Mode.
Complete Career Mode with a CAF or Roster Fighter.
Get the TKO win by damaging the opponent's legs.
KO the opponent with a soccer kick.
Win against a CAF that obtained Career Hall of Fame in Exhibition on Expert Difficulty or higher.
Win 25 fights consecutively in Title Defense Mode.
Clear Title Mode without any interruption.
Obtain a 100% completion score with both fighters in a fight in Ultimate Fights Mode.
Use 1 fighter in Career Mode to win the UFC championship in 2 weight divisions.
Win a ranked Xbox LIVE match for the first time.
Rate contents created by other players in Content Sharing.
Create a Highlight Reel.
Create a Logo and apply it to a CAF as a Tattoo.
Watch a PRIDE entrance in Exhibition once without skipping.
After a KO or TKO, land 4 finishing blows and win the match.
Obtain any level 3 move for 1 fighter in Career Mode.
Win in each division in Exhibition with Advanced Difficulty or higher.
Play an Xbox LIVE Fight Camp Sparring match.
Win 10 consecutive Fight Camp Exhibition matches.
Submission Slam or Stomp Escape the COM in Exhibition on Advanced Difficulty or Higher
Win a match on Ultimate in Exhibition or Tournament Mode with the Simulation Energy Settings.
10,000 or more shop points accumulated.
Play through each Training Game with a fighter in Career Mode.
Obtain a 4-star score in a Training Game with a fighter in Career Mode.
Use 1 fighter in Career Mode and win the WFA Championship, UFC Championship, and PRIDE Grand Prix.
Transition to all of the ground positions.
Defeat a COM on Advanced or higher in Exhibition or Tournament Mode with each Leg Submission.
Accumulate 15 hours of fight time.
Clear 25% or more of all game modes.
Play and complete a 6, 7 or 8 card event in Event Mode.
Rock an opponent with a Foot Stomp to the head in a PRIDE fight.
Create a Highlight Reel with 10 or more different fighters.
Win 5 ranked Xbox LIVE matches in a row.