Here is the full list of all 18 Everybodys Gone to the Rapture achievements.
Arrived and left Wade's surgery many, many times
Discovered the power of interactivity by doing nothing at all
Spent time waiting for a call
Rode the Witches Hat for two minutes
Simulated walking backwards for fifty seconds
Attempted to break into every caravan in Lakeside Holiday Camp
Completed the game
Triggered all of the story in the game
Found all the Chads
Read all of the Bittern books
Listened to all the radios before doing anything else
Read all of the You Are Here maps
Spent time playing with Howard's train set
Noted all of the train numbers
Used the hidden paths to return to each area in the game
Reached Stephen's bunker without ending any other story arc
Made some tasty meals using the power of nuclear energy
Waited for a pint at The Stars and The Whistler