Here is the full list of all 18 Knock-knock achievements.
Managed to hide succesfully ten times
Chose to lock The Lodger inside the cabin and remain hidden
Chose to go into the woods
Turned into a doppelganger
Entered ten haunters
Touched the weeping one
Remembered the story of the Lost Child
Found five diary pages
Found a diary page
Saw all fragments of reality
Managed to hide succesfully five times
Entered a haunter
Saw three fragments of reality
Turned the light on in every room
Managed to hide succesfully
Turned the light on in a room before a breach opened
Saw a fragment of reality
Entered a breach