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