Here is the full list of all 10 Life Eternal achievements.
You found one skeleton that used to be a friend! Maybe there are others...
You found a cryptic note from your past self. Perhaps there are others...
You totally read all the interactable books in the game.
For some reason, you were compelled to dust the dishes to make them sparkly...
Writing in a journal is often helpful if you have trouble remembering events!
You spoke to the lonely scarecrow even though you didn't have to!
You found all six cryptic letters from your past self! What do they mean?
You found all five skeletons who use to be your friends! Maybe one day they will walk with you again.
You will sleep, forevermore.
You will live, eternally.