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