Here is the full list of all 36 The Orphanage achievements.
Find a way out of your room
Solve the 5 Disc Puzzle
Solve the Chess Puzzle
Solve the Book Puzzle
Solve the Coloured Numbers Puzzle
Solve the Grandfather Clock Puzzle
Solve the Draughts Puzzle
Solve the Hex Lock Puzzle
Restore Power to the Doors in the Basement
Solve the Valve Puzzle
Solve the Piano Puzzle
Restore the Dragon's Sight
Solve the 3 Clocks Puzzle
Solve the Elements Puzzle
Find All The Coins
Find all the keys
Complete the Game Using No Batteries
Find all 6 Gems
Die for the First Time
Complete The Orphanage
Finish The Orphanage Under 3 Hours
Complete The Game Without Dying
Complete The Game Without Being Seen
Complete The Game Without Saving
Complete the game on Casual Difficulty
Complete the game on Hard Difficulty