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.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
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 Hardcore Difficulty.
Completed all campaign Acts on Insane Difficulty.
Survived all 50 waves of Horde.
Reached level 50.
Earned the Silver "Number 1" medal.
Earned the Bronze "Force Multiplier" medal.
Recovered 20 of 42 Collectibles.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Earned an Onyx medal.
Completed 5 Arcade Campaign chapters in co-op.
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.
Earned the Bronze "Loot Courtesan" medal.
Wreaked vengence upon humanity!
Reached level 15.
Survived the first 10 waves of Horde.
Completed the first 12 waves of Beast.
Killed 10 enemies in Team Deathmatch.
Completed all campaign Acts on Casual or Normal Difficulty.
Killed Myrrah.
Rescued Adam Fenix from captivity.
Executed your enemies with variety and style.
Turned off the Maelstrom device.
Passed under the Maelstrom and found Azura.
Launched the sub.
Reached level 10.
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.
Recovered 5 of 42 Collectibles.
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.
Reached level 5.
Executed an infected player and is now turning Lambent.
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.
We are the elite Onyx Guard!
Showed your friends the Horde Command Pack sights.
The Hammer of Dawn is now online!
Get 500 Silverback rocket kills in Horde (any map, any difficulty).
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.
Ignored all Loader safety guidelines and killed 10 Locusts.
Completed "RAAM's Shadow" in Standard Campaign.
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
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.
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.
Complete 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).
Earn at least one of each of the original 132 combat ribbons.
Guardian is back!
Cleaved 25 enemies with a hidden weapon.
Still standing after 20 waves - you're a natural!
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!
Complete all 12 waves of Beast on all Forces of Nature maps.
Achieve the maximum level on all fortifications in Horde mode.
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.