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