Here is the full list of all 20 Age of Empires: Castle Siege (Windows) achievements worth 200 gamerscore.
Looted 60,000 Stone
Unlocked any 6 heroes
Upgraded an Archer Tower to level 5
Looted 100,000 Wood
Built a Stable
Destroyed 30 Emplacements in Multiplayer Battles
Destroyed the Keep 100 times in Multiplayer Battles
Unlocked the Catapult from the Siege Workshop
Won 3 battles in the Historical Campaign
Looted 30,000 Food
Successfully defended your castle 10 times
Destroyed 40 Walls in Multiplayer Battles
Won 100 Crowns in Multiplayer Battles
Won 20 Multiplayer Battles
Unlocked the Raiders from the Barracks
Advanced to the Second Age
Unlock each civilization's unique troop
Advance to the Eighth Age
Win 2000 Crowns in Multiplayer Battles
Upgrade all civilizations' unique troop to level 4