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