Here is the full list of all 19 Castle Invasion: Throne Out achievements worth 1,000 gamerscore.
Unlock all Upgrades!
Defeat the King's Commander
Collect 100 Stars
Hit Every Enemy Type With the Spear
Knock a Dwarf Off a Hog
Fully Upgrade the Spear
Fully Upgrade the Bow
Defeat the Evil Archer
Defeat the King's Troll
Fully Upgrade the Crossbow
Collect 50 Stars
Collect 3 Stars in a Time Level
Complete a Night Level
Defeat the King's Dragon
Unlock the Spear
Defeat 50 Dwarves
Complete Level 1
Defeat the King!
Collect 150 Stars