As a long-term sufferer of insomnia and the brain mash of unslept nights, I am familiar with the unease of being awake in the late hours, and even as I have grown into a cranky old man, unfearing of much aside from tax and hangovers, I still get glimmers of those childish fears of what the night might really be about. This, perhaps, is what Knock, Knock is about, too. Its not the game of keeping the horrors out of the house, it is instead an attempt to reach the dark roots from which grow superstition and ritual. It is about the breakdown of reason that underlies so many fears. It is a game as much about horror as it is of horror.