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.
All achievements
Achievements they've won
Achievements they've not won
Traverse the Maze 20 Times
Traverse the Maze and Make It Out
Find the Ex-Smoker
Traverse the Maze and be Trapped
Find the Diseased Mouth
Make it to the Sewer Level
Find the Smokers Lounge
Discover the Tarred Lungs
Open All Four Drawers in the Morgue
Find the Hidden Flashlight
Find the Smokers Favorite Spot
Solve the Looping Hallway
Solve the Library Puzzle
Complete the First Interaction