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