Here is the full list of all 22 Unforgiven: Missing Memories - there are Child's Play achievements.
Completed the game
Complete the game in under 10 minutes
Complete all 5 memory sequences
Activated the Cushion memory
Activated the Hip Flask memory
Activated the Knife memory
Activated the Xylophone memory
Activated the Letter memory
Find both Diary entries
Complete the ball maze game
Activate the jack in the box
Spun the ship wheel
Hold the sword and shield
Unlock the puzzle box draw
Unlock the metal box
Solve the cipher
Get Robo Steve to print the message
Get the train running
Unlock the secret panel
Smash the pot
Unlock the toy chest
Draw on the whiteboard