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.
Defeat all opponents in Knucklebones.
Unlock all doctrines.
Have 666 gold coins.
Find all 5 locations.
Fully Upgrade Cult.
Defeat Kallamar.
Catch 1 of every fish.
Unlock a new fleece.
Reignite the lighthouse.
Defeat Heket.
Sacrifice a Follower.
Salvation awaits the fallen soul.
Gain 10 Followers.
Defeat Leshy.
Win a game of Knucklebones.
Let the Word be known.
A new world awaits.
The first devotee to the Cult of the Lamb.
Gain 5 Followers.
Defeat the first mini-boss.
A deal that cannot be undone.
Beat Leshy without taking damage.
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.
Sacrifice 10 Followers.
Unlock all weapons.
Unlock all curses.
Unlock all fleeces.
Cook a Follower meat meal.
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.