The From Outcast to Savior Add-on for CastleStorm has 8 achievements worth 100 gamerscore.
Win the King's Tournament with the mystery knight.
Hold back all the attackers in the Shiny Forest.
Rescue the Princess from the city of Stonecrest.
Secure the Royal Airport to get a flight to Vikingland.
Capture the Skyship Harbor of Vikingland.
Kill the monster protecting Bladgard.
Defeat the final boss of the Royal Guard campaign.
Earn all the stars of the Royal Guard campaign