Here is the full list of all 40 The Book of Regrets achievements.
Escape the Torture Chamber
Be killed by the Butcher in the Torture Chamber
Reach the Church
Enter the Attic
Gain entrance to the Labyrinth
Open the Furnace
Unlock the door to the end
Read about an old hero turned corrupt
Glimpse into a couple's past
Solve an artsy puzzle
Escape the Labyrinth with an item
Obtain both items in the Labyrinth in one playthrough
Obtain the Lantern
Obtain the Map
Play for a total of two hours
Collect all journal entries
Visit all areas across multiple playthroughs
Defeat all possible enemies in one playthrough
Complete the game in record time
Obtain all items across multiple playthroughs
Follow the air at the beginning and head left
Find the Hidden Room
Defeat the Monster by luring it into the fire
Defeat the Monster by exploding hazardous materials
Kill the Spider Queen
Reach the Fields with the fewest number of area changes
Finish the game having reached the Fields with max health
Defeat the Butcher
Fulfill the Cloaked Man's request
Persevere through the Demon's illusions
Resolve the confrontation with the Spider Queen peacefully
Purify the Child
Take no damage and defeat the Monster
Reject the Angel of Death's quiz
Best the Angel of Death using a fully powered weapon
Survive with the Book of Regrets
Survive with the Staff of Confidence
Get lost in the Labyrinth
Make peace in the world
Survive against all odds