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