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.
Reached level 50.
Earned an Onyx medal.
Completed all campaign Acts on Insane Difficulty.
Earned the Silver "Number 1" medal.
Executed your enemies with variety and style.
Earned the Bronze "Force Multiplier" medal.
Complete all Acts in 4 player Co-op on any difficulty.
Complete all Acts in Co-op on any difficulty.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
Survived all 50 waves of Horde.
Earned the Bronze "Loot Courtesan" medal.
Wreaked vengence upon humanity!
Completed the first 12 waves of Beast.
Reached level 25.
Your respect for the dead earned you access to Griffin's special weapons stash.
Completed one match in all six Versus multiplayer modes.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Reached level 15.
Recovered 20 of 42 Collectibles.
Completed 5 Arcade Campaign chapters in co-op.
Survived the first 10 waves of Horde.
Completed all campaign Acts on Casual or Normal Difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Reached level 10.
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.
Reached level 5.
Killed 10 enemies in Team Deathmatch.
Executed an infected player and is now turning Lambent.
Defended the Raven's Nest from Lambent Leviathan.
Woke up from a bad dream.
Your skill and experience means you’re ready for Standard Versus multiplayer.
Reach level 100 and earn every Onyx medal.
Found new places to destroy all humans.
Showed your friends the Horde Command Pack sights.
We are the elite Onyx Guard!
The Hammer of Dawn is now online!
Good ROI on that Silverback upgrade.
Used the Mauler shield to kill 10 Gears that had the temerity to fire upon you and your General.
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
As RAAM, ripped 50 Gears to shreds with your Kryll.
Honored the memory of Zeta Squad in 10 matches of Versus.
Completed "RAAM's Shadow" in Arcade Campaign.
Complete "RAAM's Shadow" in Standard Campaign on any difficulty.
Complete "RAAM's Shadow" in 4 player co-op in either Arcade or Standard mode.
Using the Loader, kill 10 Locust.
As RAAM, execute Minh 10 times in Versus MP (Standard or Casual).
Defeated the first 10 waves of Horde with every member of Zeta in your party.
Won a Versus multiplayer match as a team of five Savage Marauders (any mode).
Won a Versus multiplayer match as a team of five Recruit Claytons (any mode).
Completed all 50 waves of Horde on any of the Fenix Rising maps.
Completed all 12 waves of Beast on all Fenix Rising maps.
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.
Completed all 12 waves of Beast on all Forces of Nature maps.
Captured and "released" 20 opponents as the Savage Hunter.
Maxed out all of the Horde fortifications.
The $!*@# was taken down with extreme force.
Cleaved 25 enemies with a hidden weapon.
Completed all 50 waves of Horde on any of the Forces of Nature maps.
Found the right man for the job!
Still standing after 20 waves - you're a natural!
Win a match of Guardian on all Forces of Nature maps.
Kill 10 opponents as the leader in a round of Guardian on a Forces of Nature map.