You’re in your office when the city is attacked. You start running, leaping over a chair and out the window of a skyscraper, landing on the roof of a nearby building. An airship whizzes by, disorienting you, and suddenly a missile falls from the sky and lands in front of you. You try to jump, but it’s too late – you didn’t make it. You’re playing Canabalt HD, an enhanced version of the popular flash game Canabalt.