In Killology, players are rewarded for torturing victims, scoring points for "creativity".
But Killology isn't sick. In fact it's marketed by its millionaire creator as a deeply moral experience. Because yes, you can live out your darkest fantasies, but you don't escape their consequences.
Out on the streets, not everybody agrees with him.
"There is an instinctive revulsion against taking a human life. And that revulsion can be conquered."

Gary Owen is the winner of the George Devine, Meyer Whitworth and Pearson Best Play Awards. His other plays include Crazy Gary's Mobile Disco, The Shadow of a Boy, The Drowned World, Mrs Reynolds and the Ruffian and Love Steals Us From Loneliness. With Helen Raynor he was writer and creator of the BBC Wales series Baker Boys. His most recent theatre work includes Perfect Match for Watford Palace Theatre, where he is a creative associate, and Ring Ring, a new version of La Ronde for the Royal Welsh College of Music and Drama. In June 2015 he made his Royal Court debut with Violence and Son, directed by Hamish Pirie. Iphigenia in Splott for Sherman Cymru won Best New Play at the UK Theatre Awards 2015.