Full list of all 14 One Leaves achievements worth 1,000 gamerscore. It takes around 2-3 hours to unlock all of the achievements on Xbox One.
Traversed the Maze 20 Times
Traversed the Maze and Made It Out
Found the Smokers Lounge
Traversed the Maze and was Trapped
Found the Diseased Mouth
Made it to the Sewer Level
Discovered the Tarred Lungs
Found the Ex-Smoker
Opened All Four Drawers in the Morgue
Found the Hidden Flashlight
Found the Smokers Favorite Spot
Solved the Looping Hallway
Solved the Library Puzzle
Completed the First Interaction