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