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