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