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.
Sacrifice 10 Followers.
Beat Shamura without taking damage.
Beat Kallamar without taking damage.
Beat Heket without taking damage.
Reignite the lighthouse.
Unlock all Follower Skins.
Unlock all tarot cards.
Beat Leshy without taking damage.
Unlock all fleeces.
Defeat the One Who Waits.
Defeat Shamura.
Defeat all opponents in Knucklebones.
Find all 5 locations.
Take confession.
Unlock all weapons.
Gain 20 Followers.
Defeat Kallamar.
Unlock all doctrines.
Have 666 gold coins.
Unlock a new fleece.
Catch 1 of every fish.
Unlock all curses.
Fully Upgrade Cult.
Cook a Follower meat meal.
Defeat Heket.
Sacrifice a Follower.
Defeat the first mini-boss.
A new world awaits.
Salvation awaits the fallen soul.
Gain 5 Followers.
Gain 10 Followers.
The first devotee to the Cult of the Lamb.
A deal that cannot be undone.
Defeat Leshy.
Win a game of Knucklebones.
Let the Word be known.
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.