Roots: Tron, The Matrix. Rory mentions Xbox and PlayStation. There is a reference to The Wizard of Oz.
Dialogue Triumphs: “For a man so obsessed with peaceful solutions, you expect a lot of violence don’t you?”
Continuity: Parallife is a virtual copy of Earth. It was originally designed as a computer game, but when the human were wiped out or left Earth, their avatars become sentient and continued to live within it, given sentience by Daryl, the first artificial intelligence crated in Parallife in order to create new games. He downloads the artificial intelligences of Parallife into the reconstruction robots to rebuild Earth for when the humans return.
The Doctor carries a bottle of sunscreen. He dons a pair of sunglasses.
Amy and Rory were once on their way to a concert when their train broke down. They once visited Alton Towers.
Location: Chicago and Oklahoma, 2222.
Future History: Life on Earth has been wiped out by 2222, the Doctor noting that this occasionally happens throughout its history. Legacy is a central computer designed to contro, the demolition and rebuilding of Earth via demolition and reconstruction robots.
The Bottom Line: Witty, imaginative, and hugely entertaining. A book should never be judged by a cover, but the illustration of Daryl reading a Penguin paperback rather neatly sums it up.