Here is the full list of all 20 Age of Empires: Castle Siege (UWP) achievements worth 1,000 gamerscore.
Won 3 battles in the Historical Campaign
Advanced to the Eighth Age
Unlocked each civilization's unique troop
Advanced to the Second Age
Looted 30,000 Food
Won 20 Multiplayer Battles
Successfully defended your castle 10 times
Destroyed 30 Emplacements in Multiplayer Battles
Unlocked the Ladder Invaders from the Barracks
Unlocked the Catapult from the Siege Workshop
Won 100 Crowns in Multiplayer Battles
Upgraded an Archer Tower to level 5
Looted 100,000 Wood
Looted 60,000 Stone
Unlocked any 6 heroes
Built a Stable
Destroyed 40 Walls in Multiplayer Battles
Destroy the Keep 100 times in Multiplayer Battles
Win 2000 Crowns in Multiplayer Battles
Fully upgrade each civilization's unique troop