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