Full list of all 78 For The King achievements. It takes around 80-100 hours to unlock all of the achievements in the base game on Windows.
The base game contains 72 achievements, and there is 1 DLC pack containing 6 achievements.
Defeat 10 Mimics
Honor 15 Stone Heros
Topple 15 Crag Monsters
Defeat the Old One
Defeat Coal Heart
Use 100 herbs
Kill 10 enemies with Firearms
Find Bradach's Cabin
Slay the dragon at the top of Frostbite Peak
Have 5000 Gold
Defeat the Foul Priestess
Break a sieged town
Unlock the armory
Defeat the Royal Droll
Use 10 candies
Help Hildebrant retrace his steps
Reach the Inferno
Reach the bottom of Hildebrant's Cellar
Enter Hildebrant's Cellar
Unlock 1 item from the Lore Store
Defeat Vexor on Apprentice
Reach the top of Harazuel
Purge the Buried Temple
Fly in the Air Balloon
Clear both Demon Caves
Defeat Deimos
Solve the King's Maze
Have 1500 Gold
Kill a thief attempting to flee
Break a weapon
Defeat the Hangman
Defeat the Mind Bender
Clear the Forgotten Cellar
Defeat Lucky
Defeat the Lich's Crypt
Defeat 3 Triclops
Have 300 Gold
Honor 3 Stone Heros
Defeat the Bandit King
Revive a party member
Purge the Glittering Mines
Defeat the Cultist Camp
Clear a Cave
Defeat Disciple
Complete 1 Side Quest
Clear 5 Sea Caves in 1 game
Defeat Vexor on Journeyman
Defeat Vexor on Master
Clear the Flooded Crypt
Escape the Mage Dungeon
Survive the Lava Dungeon
Defeat the Chaos Beast
First party wipe
Complete 50 Side Quests
Honor 50 Stone Heros
Kill the Kraken
Kill 1000 Enemies
Defeat 100 Beastmen
Smash 150 Skellys
Murder 30 Hags
Crush 25 Imps
Unlock 20 items from the Lore Store
Unlock 40 items from the Lore Store
Defeat the Yeti, free her "prisoner"
Kill 5 Snowmen
Win a game of Gold Rush
Purge all 4 Water Temples
Find Captain Greenbeard's Ship
Defeat the Sea King
Defeat the Songstress
Kill 30 Fishfolk
Get killed by a suicidal enemy