Here is the full list of all 25 Coffin of Ashes achievements.
Win the “Ghost Hunt” game with the Lena twins
Save game progress over 30 times
Killed by spikes
Help the maid find her friend
Rest in the cabin to refresh yourself
Read all the missing pages of the diary
Accomplish the ending "Going in Circles"
Accomplish the ending "Rebirth"
Open the final door of the six rooms
Collect all coins for the rat
Distinguish the best spice
Meet the other two protagonists
Go back and get the letter
Put the book where it belongs
Solve the puzzle in the kid's room
Accomplish the ending "Farewell"
Solve the crystal's puzzle and awaken Delilah
That was too close to the evil spirit...
Open all the boxes without dying
Find the hall to understand more about the people
Watch all bonus CGs
Accomplish the ending "Ashes in Coffin"
Lost life in the Blood Pond
Die because of the unknown liquid
Solve the math puzzle to unlock the door