Full list of all 70 Gears of War: Judgment achievements worth 1,500 gamerscore. It takes around 50-60 hours to unlock all of the achievements in the base game.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 20 achievements worth 500 Gamerscore.
Won 10 matches of Overrun
Won one match on every map in Overrun
Killed with all classes of Locust in Overrun
Killed with all classes of COG in Overrun or Survival
Won a match on every map in all Versus modes
Won one match on every map in Domination
Won 10 rounds of Team Deathmatch
Won one match on every map in Team Deathmatch
Achieved level 50 and chose to re-up for another tour of duty
Reached level 50
Won one match in Free For All, Team Deathmatch, and Domination
Won one match on every map in Free For All
Reached level 40
Equipped your first Medal
Completed all Declassified Missions on Insane difficulty
Completed all Campaign Chapters on at least Normal difficulty
Completed all Campaign Chapters on at least Hardcore difficulty
Completed all Campaign Chapters on Insane difficulty
Completed all Declassified missions
Attained all Stars on Insane Difficulty
Reached level 30
Attained 100 Stars on at least Hardcore Difficulty
Watched Aftermath teaser
Earned at least one Onyx medal
Attained 75 Stars on at least Normal Difficulty
Completed wave 10 on all maps in Survival mode
Reached level 20
Recovered all 48 COG Tags during the Campaign
Completed Aftermath
Completed Courthouse
Completed all Campaign Chapters on at least Casual difficulty
Completed all Campaign Chapters in Co-op
Completed Downtown Halvo Bay
Reached level 10
Completed Onyx Point
Recovered 25 COG Tags during the Campaign
Completed at least 20 Declassified missions
Completed Seahorse Hills
Attained 50 Stars on at least Casual Difficulty
Unlocked Aftermath
Completed Halvo Bay Military Academy
Earned 3 unique Ribbons in any section
Recovered 10 COG Tags during the Campaign
Reached level 5
Completed Museum Of Military Glory
Played any section in 4 player Co-Op
Completed your first Declassified mission
Earn the Onyx "War Supporter" medal
Achieve level 50 a second time and choose to re-up for another tour
Achieve level 50 a third time and choose to re-up for another tour
Earned 50 Double ribbons with the Booshka on Terminal
Got a Double while emerging as a Corpser
Won a Team Death Match game with the entire team wearing the Car 13 Armor skin
Played 10 matches total on BloodDrive
Earned the You’re It ribbon on Boneyard
Placed first in Free For All in Boneyard 5 times
Earned a killing spree with the Boomshield on Boneyard
Revive 100 total teammates on Terminal as a Medic
Kill 100 enemies with each Locust
Win Hardcore Survival on Terminal with 5 Soldiers
Won a TDM, DOM, and BT match with your entire team wearing the UIR Armor skin
Scored a flag cap on Streets, Rig, Gondola, Library, Lost City, Museum, and Checkout
Scored 5 flags in BT as Paduk
Killed the flag carrier a total of 20 times
Got a kill with each pickup weapon in FFA during a single game on the map Lost City
Earned the Tree House Predator ribbon on Ward
Got a multi-kill while playing as an enraged Rager on Ward
Destroyed the generator in under 8 minutes on any DLC map
Finish wave 10 of Survival at the first e-hole on Ward on at least Normal difficulty
Win public/ranked game of Execution on Museum with all players using Gold character and weapon skins