Here is the full list of all 15 Stairs achievements.
Complete Busy Vagabonds, Family Ties, Come Prepared & Honeyed Words
Take all the pictures in Remens' Reformatory
Find all the hidden secrets in the game
Find all notes in Remens' Reformatory
Find all notes in Reed's Dungeon
Take all the pictures in Reed's Dungeon
Take all the pictures in Valerie's Prison
Find all notes in Valerie's Prison
Take all the pictures in the old factory
Complete Doctor's Prescription, Final Meal & The Devoted