Here is the full list of all 56 Gears of War: Ultimate Edition achievements worth 1,250 gamerscore.
Complete tutorial path on any difficulty
Story progression in Act 1 Chapter 1 (on any difficulty)
Story progression in Act 1 Chapter 6 (on any difficulty)
Story progression in Act 1 Chapter 7 (on any difficulty)
Story progression in Act 1 Chapter 8 (on any difficulty)
Story progression in Act 2 Chapter 2 (on any difficulty)
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)
Perform 25 perfect active reloads (on any difficulty)
Perform 5 perfect active reloads in a row (on any difficulty)
Kill 3 enemies at once 10 different times (on any difficulty)
Complete 1 co-op chapter in co-op (on any difficulty)
Complete 10 different chapters in co-op (on any difficulty)
Complete all acts in co-op (on any difficulty)
Revive 100 teammates in Versus multiplayer (social or competitive)
Finish playing a Versus match (social or competitive)
Finish with the highest point in a Versus match (social or competitive)
Win a match in every Versus game type (social or competitive)
Win a match in every Versus map (social or competitive)
Win 10 Versus matches without losing a round (social or competitive)
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 5
Reach level 10
Reach level 25
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
Play one Versus Match with a Custom Weapon Skin
Win 25 matches in Team Deathmatch
Close all 4 e-holes around the fountain in Fish in a Barrel without any Locust fully emerging