Here is the full list of all 56 Gears of War: Ultimate Edition (Windows) achievements worth 1,250 gamerscore.
Story progression in Act 5 Chapter 8 (on any difficulty)
Story progression in Act 5 Chapter 6 (on any difficulty)
Finish playing a Versus match (social or competitive)
Win a match in every Versus map (social or competitive)
Win 25 matches in Team Deathmatch
Story progression in Act 3 Chapter 5 (on any difficulty)
Defeat General RAAM in co-op on Insane without either player being DBNO
Win 10 Versus matches without losing a round (social or competitive)
Complete all acts on Normal Difficulty
Kill 3 enemies at once 10 different times (on any difficulty)
Reach level 10
Story progression in Act 1 Chapter 6 (on any difficulty)
Reach level 25
Complete all acts on Insane Difficulty
Reach level 5
Win 25 matches in Boxes (social or competitive)
Complete 1 co-op chapter in co-op (on any difficulty)
Story progression in Act 3 Chapter 6 (on any difficulty)
Complete 10 different chapters in co-op (on any difficulty)
Story progression in Act 2 Chapter 4 (on any difficulty)
Finish with the highest point in a Versus match (social or competitive)
Spot 100 enemies ending in a kill in Versus (social or competitive)
Revive 100 teammates in Versus multiplayer (social or competitive)
Story progression in Act 2 Chapter 8 (on any difficulty)
Recover all 33 COG tags (on any difficulty)
Complete 100 matches in ring-based game types on Xbox Live and capture 3 objectives in each match
Complete all acts in co-op (on any difficulty)
Recover 11 COG tags (on any difficulty)
Story progression in Act 4 Chapter 2 (on any difficulty)
Story progression in Act 4 Chapter 6 (on any difficulty)
Play one Versus Match with a Custom Weapon Skin
Story progression in Act 3 Chapter 4 (on any difficulty)
Story progression in Act 5 Chapter 3 (on any difficulty)
Read one full comic
Kill an enemy with every weapon in Versus (social or competitive)
Complete all acts on Casual Difficulty
Recover 22 COG tags (on any difficulty)
Win a match in every Versus game type (social or competitive)
Story progression in Act 2 Chapter 2 (on any difficulty)
Story progression in Act 1 Chapter 8 (on any difficulty)
Win 20 rounds in ring-based game types on Xbox Live by shutting out the opposing team
Story progression in Act 1 Chapter 1 (on any difficulty)
Story progression in Act 5 Chapter 2
Close all 4 e-holes around the fountain in Fish in a Barrel without any Locust fully emerging
Complete tutorial path on any difficulty
Story progression in Act 1 Chapter 7 (on any difficulty)
Story progression in Act 4 Chapter 1 (on any difficulty)
Reach level 100 and re-up
Perform 25 perfect active reloads (on any difficulty)
Kill 10,000 people in Versus matches
Perform 5 perfect active reloads in a row (on any difficulty)
Complete all acts on Hardcore Difficulty
Story progression in Act 2 Chapter 6 (on any difficulty)
Story progression in Act 5 Chapter 5 (on any difficulty)
Story progression in Act 3 Chapter 2 (on any difficulty)