I pulled up a map of the town and traced a route from my current location to Halliday’s childhood home. It was about a mile to the north. I pointed my avatar in that direction and began to run. Looking around, I was astounded at the painstaking attention to detail. I’d read that Halliday had done all of the coding himself, drawing on his memories to re-create his hometown exactly as it was during his childhood. He’d used old street maps, phone books, photographs, and video footage for reference, to make everything as authentic and accurate as possible.