Full list of all 56 For The King achievements worth 1,000 gamerscore. It takes around 60-80 hours to unlock all of the achievements on Xbox One.
Complete 50 Side Quests
Defeat Vexor on Master
Defeat Vexor on Journeyman
Survive the Lava Dungeon
Escape the Mage Dungeon
Defeat the Chaos Beast
Clear the Flooded Crypt
Win a game of Gold Rush
Smash 150 Skellys
Topple 15 Crag Monsters
Defeat the Sea King
Purge all 4 Water Temples
Defeat the Songstress
Honor 50 Stone Heroes
Find Captain Greenbeard's Ship
Unlock 40 items from the Lore Store
Kill 5 Snowmen
Defeat Deimos
Defeat the Foul Priestess
Honor 15 Stone Heroes
Unlock 20 items from the Lore Store
Reach the Inferno
Reach the bottom of Hildebrant's Cellar
Defeat Disciple
Slay the dragon at the top of Frostbite Peak
Use 100 herbs
Defeat Lucky
Unlock the armory
Defeat the Yeti, free her "prisoner"
Break a sieged town
Help Hildebrant retrace his steps
First party wipe
Revive a party member
Defeat Vexor on Apprentice
Kill 10 enemies with Firearms
Reach the top of Harazuel
Kill the Kraken
Have 5000 Gold
Clear 5 Sea Caves in 1 game
Purge the Buried Temple
Defeat Coal Heart
Clear both Demon Caves
Break a weapon
Defeat the Hangman
Use 10 candies
Solve the King's Maze
Have 1500 Gold
Defeat the Lich's Crypt
Defeat the Old One
Defeat the Bandit King
Defeat the Mind Bender
Clear the Forgotten Cellar
Purge the Glittering Mines
Kill a thief attempting to flee
Defeat the Cultist Camp
Defeat the Royal Droll