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.
Reached level 50.
Earned the Onyx "War Supporter" medal.
Earned the Bronze "Force Multiplier" medal.
Recovered all 42 Collectibles.
Complete all Acts in 4 player Co-op on any difficulty.
Recovered all 15 COG Tags.
Rescued Adam Fenix from captivity.
Complete all Acts in Co-op on any difficulty.
Completed all campaign Acts on Casual or Normal Difficulty.
Completed all campaign Acts on Hardcore Difficulty.
Completed all campaign Acts on Insane Difficulty.
Turned off the Maelstrom device.
Your respect for the dead earned you access to Griffin's special weapons stash.
Reached level 25.
Found and activated the fuel pump.
Drove from Anvil Gate to Mercy.
Maxed the Consecutive Match Bonus in Versus multiplayer.
Defeated the Lambent Berserker.
Defended Anvil Gate from the Locust siege.
Recovered 20 of 42 Collectibles.
Grabbed a Locust Gas Barge to travel to Anvil Gate.
Discovered the location of Adam Fenix.
Passed under the Maelstrom and found Azura.
Launched the sub.
Found enough fuel to get to Endeavor naval base.
Killed Myrrah.
Killed 10 enemies in Team Deathmatch.
Completed one match in all six Versus multiplayer modes.
Reached level 15.
Arrived safely, kinda, at Anvil Gate.
Blew up the Lambent Leviathan from the bridge.
Defended and escaped from Cougar Stadium.
Completed 5 Arcade Campaign chapters in co-op.
Found food and ammo in Hanover.
Recovered 5 of 42 Collectibles.
Defended the Raven's Nest from Lambent Leviathan.
Woke up from a bad dream.
Completed the first 12 waves of Beast.
Wreaked vengence upon humanity!
Earned an Onyx medal.
Earned the Bronze "Loot Courtesan" medal.
Survived all 50 waves of Horde.
Reached level 10.
Executed an infected player and is now turning Lambent.
Reached level 5.
Survived the first 10 waves of Horde.
Your skill and experience means you’re ready for Standard Versus multiplayer.
Get a kill with every possible execution finishing move (any mode).
Earn the Silver "Number 1" medal.
Reach level 100 and earn every Onyx medal.
Found new places to destroy all humans.
Showed your friends the Horde Command Pack sights.
Defeat a Boss Wave as 5 Onyx Guards (Hardcore difficulty).
The Hammer of Dawn is now online!
Get 500 Silverback rocket kills in Horde (any map, any difficulty).
Honored the memory of Zeta Squad in 10 matches of Versus.
Completed "RAAM's Shadow" in Arcade Campaign.
Ignored all Loader safety guidelines and killed 10 Locusts.
Complete "RAAM's Shadow" in Standard Campaign on any difficulty.
Complete "RAAM's Shadow" in 4 player co-op in either Arcade or Standard mode.
As RAAM, kill 50 Gears using your Kryll.
As Mauler, kill 10 Gears by reflecting their bullets using your shield.
Using the Hammer of Dawn Command Center, kill 50 Locust.
As RAAM, execute Minh 10 times in Versus MP (Standard or Casual).
Complete waves 1-10 of Horde with 5 players as Zeta (Barrick, Tai, Minh, Valera and Jace).
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).
Completed all 50 waves of Horde on any of the Fenix Rising maps.
Complete all 12 waves of Beast on all Fenix Rising maps.
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.
Guardian is back!
Completed all 12 waves of Beast on all Forces of Nature maps.
Cleaved 25 enemies with a hidden weapon.
Still standing after 20 waves - you're a natural!
Found the right man for the job!
Captured and "released" 20 opponents as the Savage Hunter.
Completed all 50 waves of Horde on any of the Forces of Nature maps.
The $!*@# was taken down with extreme force.
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.