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.
Recovered all 42 Collectibles.
Earned the Bronze "Force Multiplier" medal.
Earned the Onyx "War Supporter" medal.
Complete all Acts in 4 player Co-op on any difficulty.
Wreaked vengence upon humanity!
Recovered all 15 COG Tags.
Earned the Silver "Number 1" medal.
Complete all Acts in Co-op on any difficulty.
Reached level 50.
Completed all campaign Acts on Insane Difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Earned an Onyx medal.
Your respect for the dead earned you access to Griffin's special weapons stash.
Earned the Bronze "Loot Courtesan" medal.
Reached level 25.
Recovered 20 of 42 Collectibles.
Survived all 50 waves of Horde.
Executed an infected player and is now turning Lambent.
Killed 10 enemies in Team Deathmatch.
Reached level 15.
Completed 5 Arcade Campaign chapters in co-op.
Reached level 10.
Survived the first 10 waves of Horde.
Recovered 5 of 42 Collectibles.
Completed all campaign Acts on Casual or Normal 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.
Reached level 5.
Discovered the location of Adam Fenix.
Blew up the Lambent Leviathan from the bridge.
Completed the first 12 waves of Beast.
Defended and escaped from Cougar Stadium.
Found food and ammo in Hanover.
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.
Get a kill with every possible execution finishing move (any mode).
Reach level 100 and earn every Onyx medal.
Complete one match of all six Versus game modes (Standard or Casual).
Earn the maximum Consecutive Match Bonus in Versus multiplayer (Standard or Casual).
We are the elite Onyx Guard!
Showed your friends the Horde Command Pack sights.
Found new places to destroy all humans.
Good ROI on that Silverback upgrade.
The Hammer of Dawn is now online!
Ignored all Loader safety guidelines and killed 10 Locusts.
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
Completed "RAAM's Shadow" in Standard Campaign.
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.
As Mauler, kill 10 Gears by reflecting their bullets using your shield.
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.
Completed all 12 waves of Beast on all Fenix Rising maps.
Completed 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.
Still standing after 20 waves - you're a natural!
Cleaved 25 enemies with a hidden weapon.
Completed all 12 waves of Beast on all Forces of Nature maps.
Maxed out all of the Horde fortifications.
Captured and "released" 20 opponents as the Savage Hunter.
Completed all 50 waves of Horde on any of the Forces of Nature maps.
Found the right man for the job!
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.