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.
Defeat the One Who Waits.
Sacrifice 10 Followers.
Unlock all fleeces.
Unlock all Follower Skins.
Unlock all tarot cards.
Defeat all opponents in Knucklebones.
Have 666 gold coins.
Defeat Shamura.
Beat Shamura without taking damage.
Find all 5 locations.
Cook a Follower meat meal.
Beat Heket without taking damage.
Defeat Kallamar.
Beat Kallamar without taking damage.
Take confession.
Gain 20 Followers.
Unlock all doctrines.
Unlock all weapons.
Fully Upgrade Cult.
Defeat Heket.
Sacrifice a Follower.
Unlock all curses.
Unlock a new fleece.
Reignite the lighthouse.
Catch 1 of every fish.
Gain 10 Followers.
Salvation awaits the fallen soul.
Beat Leshy without taking damage.
Defeat Leshy.
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.