Full list of all 48 Cult of the Lamb achievements. It takes around 15-20 hours to unlock all of the achievements in the base game on Windows.
The base game contains 37 achievements, and there are 2 DLC packs containing 11 achievements.
Sacrifice 10 Followers.
Beat Shamura without taking damage.
Beat Kallamar without taking damage.
Beat Heket without taking damage.
Beat Leshy without taking damage.
Unlock all Follower Skins.
Unlock all fleeces.
Defeat the One Who Waits.
Defeat Kallamar.
Defeat Shamura.
Unlock all tarot cards.
Defeat all opponents in Knucklebones.
Find all 5 locations.
Gain 20 Followers.
Take confession.
Unlock all curses.
Unlock all weapons.
Unlock a new fleece.
Catch 1 of every fish.
Unlock all doctrines.
Have 666 gold coins.
Fully Upgrade Cult.
Defeat Heket.
Gain 10 Followers.
Reignite the lighthouse.
Defeat Leshy.
Cook a Follower meat meal.
Sacrifice a Follower.
Salvation awaits the fallen soul.
Win a game of Knucklebones.
A new world awaits.
Gain 5 Followers.
Let the Word be known.
Defeat the first mini-boss.
The first devotee to the Cult of the Lamb.
A deal that cannot be undone.
No longer a servant, no less than a God.
Collect all Relics.
Get your Gold back from Midas.
Complete a row in Purgatory.
Unlock all lore.
Unlock all outfits.
Have 12 Disciples.
Completely Upgrade the Temple.
Hatch 5 eggs.