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.
Blew up the Lambent Leviathan from the bridge.
Discovered the location of Adam Fenix.
Grabbed a Locust Gas Barge to travel to Anvil Gate.
Recovered all 42 Collectibles.
Recovered all 15 COG Tags.
Reached level 10.
Earned the Silver "Number 1" medal.
Survived the first 10 waves of Horde.
Earned the Onyx "War Supporter" medal.
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.
Reached level 50.
Recovered 20 of 42 Collectibles.
Reached level 25.
Recovered 5 of 42 Collectibles.
Earned the Bronze "Loot Courtesan" medal.
Survived all 50 waves of Horde.
Completed 5 Arcade Campaign chapters in co-op.
Completed one match in all six Versus multiplayer modes.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Earned an Onyx medal.
Reached level 15.
Earned the Bronze "Force Multiplier" medal.
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.
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.
Killed 10 enemies in Team Deathmatch.
Reached level 5.
Executed an infected player and is now turning Lambent.
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.
Wreaked vengence upon humanity!
Completed the first 12 waves of Beast.
Your skill and experience means you’re ready for Standard Versus multiplayer.
Reach level 100 and earn every Onyx medal.
Showed your friends the Horde Command Pack sights.
Found new places to destroy all humans.
We are the elite Onyx Guard!
Good ROI on that Silverback upgrade.
The Hammer of Dawn is now online!
Honored the memory of Zeta Squad in 10 matches of Versus.
Completed "RAAM's Shadow" in Arcade Campaign.
Showed 50 Locusts the meaning of sky-fire with HOD Command Center.
As RAAM, ripped 50 Gears to shreds with your Kryll.
As RAAM, made sure Minh never forgets that day outside the House of Sovereigns.
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 Standard Campaign.
Ignored all Loader safety guidelines and killed 10 Locusts.
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.
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).
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.
Found the right man for the job!
Complete all 12 waves of Beast on all Forces of Nature maps.
Complete 20 consecutive waves of Horde on any Forces of Nature map without going down or dying.
Complete all 50 waves of Horde on any of the Forces of Nature maps.
Get 25 kills with any of the hidden elementally charged Cleavers in Horde.
Achieve the maximum level on all fortifications in Horde mode.
Win a match of Guardian on all Forces of Nature maps.
Bag and Tag 20 opponents while playing as the Savage Hunter in Versus multiplayer (any 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.