The September Update Title update for Gears of War 4 has 18 achievements worth 500 gamerscore.
Reach Level 20
Complete eight Campaign Chapters (any difficulty)
Earn 5 Ribbons
Upgrade 3 skill cards
Complete two Campaign Chapters (any difficulty)
Complete three Campaign Chapters (any difficulty)
Complete seven Campaign Chapters (any difficulty)
Reach level 2 in one Horde class
Complete four Campaign Chapters (any difficulty)
Complete five Campaign Chapters (any difficulty)
Complete six Campaign Chapters (any difficulty)
Reach Level 5
Reach Level 15
Kill 25 enemies in Co-op Versus matches
Complete two Campaign Acts in Co-op (any difficulty)
Complete twelve Campaign Chapters (any difficulty)
Complete twenty Campaign Chapters (any difficulty)
Complete the Prologue in Co-op (any difficulty)