Here is the full list of all 56 Gears of War: Ultimate Edition achievements worth 1,250 gamerscore.
Won a match on every Versus map
Revived 100 teammates in Versus multiplayer
Won a match in every Versus game type
Rescued Augustus Cole in the House of Sovereigns
Rescued Damon Baird from the Tomb of the Unknown
Killed the Berserker in the Tomb of the Unknown
Made a Deal with Franklin
Completed 1 co-op chapter in co-op
Escaped from the Slab
Completed tutorial path on any difficulty
Reached level 25
Won 25 matches in Team Deathmatch
Won 10 Versus matches without losing a round
Reached level 10
Reached level 5
Performed 25 perfect active reloads
Finished with the highest points in a Versus match
Performed 5 perfect active reloads in a row
Finished playing a Versus match
Played one Versus Match with a Custom Weapon Skin
Story progression in Act 2 Chapter 4 (on any difficulty)
Story progression in Act 2 Chapter 6 (on any difficulty)
Story progression in Act 2 Chapter 8 (on any difficulty)
Story progression in Act 3 Chapter 2 (on any difficulty)
Story progression in Act 3 Chapter 4 (on any difficulty)
Story progression in Act 3 Chapter 5 (on any difficulty)
Story progression in Act 3 Chapter 6 (on any difficulty)
Spot 100 enemies ending in a kill in Versus (social or competitive)
Story progression in Act 4 Chapter 1 (on any difficulty)
Story progression in Act 4 Chapter 2 (on any difficulty)
Story progression in Act 4 Chapter 6 (on any difficulty)
Story progression in Act 5 Chapter 2
Story progression in Act 5 Chapter 3 (on any difficulty)
Story progression in Act 5 Chapter 5 (on any difficulty)
Story progression in Act 5 Chapter 6 (on any difficulty)
Story progression in Act 5 Chapter 8 (on any difficulty)
Complete all acts on Casual Difficulty
Complete all acts on Normal Difficulty
Complete all acts on Hardcore Difficulty
Complete all acts on Insane Difficulty
Recover 11 COG tags (on any difficulty)
Recover 22 COG tags (on any difficulty)
Recover all 33 COG tags (on any difficulty)
Kill 3 enemies at once 10 different times (on any difficulty)
Complete 10 different chapters in co-op (on any difficulty)
Complete all acts in co-op (on any difficulty)
Kill 10,000 people in Versus matches
Complete 100 matches in ring-based game types on Xbox Live and capture 3 objectives in each match
Win 20 rounds in ring-based game types on Xbox Live by shutting out the opposing team
Win 25 matches in Boxes (social or competitive)
Reach level 100 and re-up
Kill an enemy with every weapon in Versus (social or competitive)
Read one full comic
Defeat General RAAM in co-op on Insane without either player being DBNO
Close all 4 e-holes around the fountain in Fish in a Barrel without any Locust fully emerging