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.
Woke up from a bad dream.
Defended the Raven's Nest from Lambent Leviathan.
Found food and ammo in Hanover.
Defended and escaped from Cougar Stadium.
Blew up the Lambent Leviathan from the bridge.
Discovered the location of Adam Fenix.
Grabbed a Locust Gas Barge to travel to Anvil Gate.
Arrived safely, kinda, at Anvil Gate.
Defended Anvil Gate from the Locust siege.
Defeated the Lambent Berserker.
Drove from Anvil Gate to Mercy.
Found and activated the fuel pump.
Found enough fuel to get to Endeavor naval base.
Launched the sub.
Passed under the Maelstrom and found Azura.
Turned off the Maelstrom device.
Rescued Adam Fenix from captivity.
Killed Myrrah.
Completed all campaign Acts on Casual or Normal Difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Completed all campaign Acts on Insane Difficulty.
Recovered 5 of 42 Collectibles.
Recovered 20 of 42 Collectibles.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
Complete all Acts in Co-op on any difficulty.
Complete all Acts in 4 player Co-op on any difficulty.
Reached level 5.
Reached level 10.
Reached level 15.
Reached level 25.
Reached level 50.
Executed your enemies with variety and style.
Wreaked vengence upon humanity!
Survived all 50 waves of Horde.
Earned the Bronze "Loot Courtesan" medal.
Earned the Bronze "Force Multiplier" medal.
Earned the Silver "Number 1" medal.
Earned an Onyx medal.
Survived the first 10 waves of Horde.
Completed the first 12 waves of Beast.
Completed 5 Arcade Campaign chapters in co-op.
Executed an infected player and is now turning Lambent.
Your respect for the dead earned you access to Griffin's special weapons stash.
Completed one match in all six Versus multiplayer modes.
Your skill and experience means you’re ready for Standard Versus multiplayer.
Killed 10 enemies in Team Deathmatch.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Earned the Onyx "War Supporter" medal.
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!
Ignored all Loader safety guidelines and killed 10 Locusts.
As RAAM, made sure Minh never forgets that day outside the House of Sovereigns.
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
As RAAM, ripped 50 Gears to shreds with your Kryll.
Completed "RAAM's Shadow" in 4 player co-op.
Completed "RAAM's Shadow" in Arcade Campaign.
Honored the memory of Zeta Squad in 10 matches of Versus.
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.
Defeated the first 10 waves of Horde with every member of Zeta in your party.
Level 100 and going back for more!
Completed all 12 waves of Beast on all 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).
Completed all 50 waves of Horde on any of the Fenix Rising maps.
Achieve level 100 a second time and choose to re-up for another tour.
Earned all 132 combat ribbons.
The $!*@# was taken down with extreme force.
Maxed out all of the Horde fortifications.
Completed all 12 waves of Beast on all Forces of Nature maps.
Guardian is back!
Captured and "released" 20 opponents as the Savage Hunter.
Cleaved 25 enemies with a hidden weapon.
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!
Kill 10 opponents as the leader in a round of Guardian on a Forces of Nature map.