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.
Completed one match in all six Versus multiplayer modes.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Killed 10 enemies in Team Deathmatch.
Reached level 50.
Earned the Silver "Number 1" medal.
Completed all campaign Acts on Hardcore Difficulty.
Completed all campaign Acts on Insane Difficulty.
Executed your enemies with variety and style.
Earned the Bronze "Force Multiplier" medal.
Earned an Onyx medal.
Reached level 25.
Complete all Acts in 4 player Co-op on any difficulty.
Complete all Acts in Co-op on any difficulty.
Completed all campaign Acts on Casual or Normal Difficulty.
Killed Myrrah.
Rescued Adam Fenix from captivity.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
Turned off the Maelstrom device.
Passed under the Maelstrom and found Azura.
Launched the sub.
Found enough fuel to get to Endeavor naval base.
Your respect for the dead earned you access to Griffin's special weapons stash.
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.
Recovered 20 of 42 Collectibles.
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.
Completed 5 Arcade Campaign chapters in co-op.
Found food and ammo in Hanover.
Recovered 5 of 42 Collectibles.
Defended the Raven's Nest from Lambent Leviathan.
Woke up from a bad dream.
Survived all 50 waves of Horde.
Reached level 15.
Earned the Bronze "Loot Courtesan" medal.
Reached level 10.
Wreaked vengence upon humanity!
Executed an infected player and is now turning Lambent.
Completed the first 12 waves of Beast.
Reached level 5.
Survived the first 10 waves of Horde.
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!
Good ROI on that Silverback upgrade.
The Hammer of Dawn is now online!
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
Completed "RAAM's Shadow" in Standard Campaign.
Used the Mauler shield to kill 10 Gears that had the temerity to fire upon you and your General.
Completed "RAAM's Shadow" in Arcade Campaign.
As RAAM, ripped 50 Gears to shreds with your Kryll.
Complete "RAAM's Shadow" in 4 player co-op in either Arcade or Standard mode.
Using the Loader, kill 10 Locust.
Play 10 matches of Versus as a member of Zeta (Barrick, Tai, Minh, or Valera)(Standard or Casual).
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.
Level 100 - so nice, I did it twice.
Level 100 and going back for more!
Completed all 12 waves of Beast on all Fenix Rising maps.
Completed all 50 waves of Horde on any of the Fenix Rising maps.
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).
Earn at least one of each of the original 132 combat ribbons.
Captured and "released" 20 opponents as the Savage Hunter.
Cleaved 25 enemies with a hidden weapon.
Completed all 12 waves of Beast on all Forces of Nature maps.
Completed all 50 waves of Horde on any of the Forces of Nature maps.
Still standing after 20 waves - you're a natural!
Found the right man for the job!
Maxed out all of the Horde fortifications.
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.
Kill a Lambent Berserker with a team comprised of 5 Forces of Nature characters in Horde.