Full list of all 82 Gears of War 3 achievements worth 2,000 gamerscore. It takes around 1000 hours to unlock all of the achievements in the base game.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 7 DLC packs containing 32 achievements worth 1,000 Gamerscore.
Earned the Onyx "War Supporter" medal.
Complete all Acts in 4 player Co-op on any difficulty.
Your respect for the dead earned you access to Griffin's special weapons stash.
Recovered 20 of 42 Collectibles.
Earned an Onyx medal.
Completed 5 Arcade Campaign chapters in co-op.
Complete all Acts in Co-op on any difficulty.
Survived all 50 waves of Horde.
Earned the Bronze "Loot Courtesan" medal.
Reached level 50.
Completed all campaign Acts on Casual or Normal Difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Killed Myrrah.
Rescued Adam Fenix from captivity.
Turned off the Maelstrom device.
Passed under the Maelstrom and found Azura.
Launched the sub.
Found enough fuel to get to Endeavor naval base.
Found and activated the fuel pump.
Drove from Anvil Gate to Mercy.
Defeated the Lambent Berserker.
Defended Anvil Gate from the Locust siege.
Arrived safely, kinda, at Anvil Gate.
Grabbed a Locust Gas Barge to travel to Anvil Gate.
Discovered the location of Adam Fenix.
Blew up the Lambent Leviathan from the bridge.
Defended and escaped from Cougar Stadium.
Recovered 5 of 42 Collectibles.
Found food and ammo in Hanover.
Defended the Raven's Nest from Lambent Leviathan.
Woke up from a bad dream.
Reached level 25.
Survived the first 10 waves of Horde.
Completed the first 12 waves of Beast.
Reached level 15.
Killed 10 enemies in Team Deathmatch.
Reached level 10.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Executed an infected player and is now turning Lambent.
Reached level 5.
Your skill and experience means you’re ready for Standard Versus multiplayer.
Complete all campaign Acts on Insane Difficulty (Standard or Arcade).
Recover all 42 Campaign Collectibles (any difficulty, Standard or Arcade).
Recover all 15 COG Tags during the Campaign (any difficulty, Standard or Arcade).
Get a kill with every possible execution finishing move (any mode).
Get a kill with every Locust monster in Beast mode (any difficulty).
Earn the Bronze "Force Multiplier" medal.
Earn the Silver "Number 1" medal.
Reach level 100 and earn every Onyx medal.
Complete one match of all six Versus game modes (Standard or Casual).
Host a private Horde Match with a party of 5 players on any Horde Command Pack map (any difficulty).
Host a private Beast Match with a party of 5 players on any Horde Command Pack map (any difficulty).
Defeat a Boss Wave as 5 Onyx Guards (Hardcore difficulty).
Get 500 Silverback rocket kills in Horde (any map, any difficulty).
Achieve Level 4 in Horde Command Center fortifications.
Completed "RAAM's Shadow" in Standard Campaign.
Honored the memory of Zeta Squad in 10 matches of Versus.
As RAAM, ripped 50 Gears to shreds with your Kryll.
Complete "RAAM's Shadow" in Arcade Campaign on any difficulty.
Complete "RAAM's Shadow" in 4 player co-op in either Arcade or Standard mode.
As Mauler, kill 10 Gears by reflecting their bullets using your shield.
Using the Hammer of Dawn Command Center, kill 50 Locust.
Using the Loader, kill 10 Locust.
As RAAM, execute Minh 10 times in Versus MP (Standard or Casual).
Complete waves 1-10 of Horde with 5 players as Zeta (Barrick, Tai, Minh, Valera and Jace).
Complete all 12 waves of Beast on all Fenix Rising maps.
Complete all 50 waves of Horde on any of the Fenix Rising maps.
Win a Versus multiplayer match as a team of five Recruit Claytons (any mode).
Win a Versus multiplayer match as a team of five Savage Marauders (any mode).
Achieve level 100 and choose to re-up for another tour of duty.
Achieve level 100 a second time and choose to re-up for another tour.
Earn at least one of each of the original 132 combat ribbons.
Complete all 12 waves of Beast on all Forces of Nature maps.
Complete 20 consecutive waves of Horde on any Forces of Nature map without going down or dying.
Complete all 50 waves of Horde on any of the Forces of Nature maps.
Get 25 kills with any of the hidden elementally charged Cleavers in Horde.
Achieve the maximum level on all fortifications in Horde mode.
Win a match of Guardian on all Forces of Nature maps.
Build or repair 50,000 worth of fortifications as Mechanic Baird LE.
Bag and Tag 20 opponents while playing as the Savage Hunter in Versus multiplayer (any mode).
Kill 10 opponents as the leader in a round of Guardian on a Forces of Nature map.
Kill a Lambent Berserker with a team comprised of 5 Forces of Nature characters in Horde.