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.
Survived all 50 waves of Horde.
Reached level 50.
Earned the Onyx "War Supporter" medal.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Completed one match in all six Versus multiplayer modes.
Earned the Bronze "Loot Courtesan" medal.
Reached level 25.
Earned the Silver "Number 1" medal.
Complete all Acts in 4 player Co-op on any difficulty.
Completed 5 Arcade Campaign chapters in co-op.
Completed the first 12 waves of Beast.
Survived the first 10 waves of Horde.
Earned the Bronze "Force Multiplier" medal.
Wreaked vengence upon humanity!
Reached level 15.
Complete all Acts in Co-op on any difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Earned an Onyx medal.
Completed all campaign Acts on Insane Difficulty.
Executed your enemies with variety and style.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
Your respect for the dead earned you access to Griffin's special weapons stash.
Reached level 10.
Completed all campaign Acts on Casual or Normal Difficulty.
Killed Myrrah.
Rescued Adam Fenix from captivity.
Recovered 20 of 42 Collectibles.
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.
Killed 10 enemies in Team Deathmatch.
Reached level 5.
Executed an infected player and is now turning Lambent.
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.
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!
As RAAM, made sure Minh never forgets that day outside the House of Sovereigns.
Honored the memory of Zeta Squad in 10 matches of Versus.
Used the Mauler shield to kill 10 Gears that had the temerity to fire upon you and your General.
Completed "RAAM's Shadow" in 4 player co-op.
Completed "RAAM's Shadow" in Arcade Campaign.
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.
As RAAM, ripped 50 Gears to shreds with your Kryll.
Defeated the first 10 waves of Horde with every member of Zeta in your party.
Completed all 50 waves of Horde on any of the Fenix Rising maps.
Level 100 - so nice, I did it twice.
Completed all 12 waves of Beast on all Fenix Rising maps.
Level 100 and going back for more!
Won a Versus multiplayer match as a team of five Recruit Claytons (any mode).
Won a Versus multiplayer match as a team of five Savage Marauders (any mode).
Earned all 132 combat ribbons.
Maxed out all of the Horde fortifications.
Completed all 50 waves of Horde on any of the Forces of Nature maps.
Still standing after 20 waves - you're a natural!
Guardian is back!
Found the right man for the job!
Cleaved 25 enemies with a hidden weapon.
Completed all 12 waves of Beast on all Forces of Nature maps.
Led by example and killed 10 opponents as Guardian leader.
The $!*@# was taken down with extreme force.
Captured and "released" 20 opponents as the Savage Hunter.