It's less Dungeons & Dragons than slick office space, with 100 designers, artists, programmers and audio technicians sitting together in a sleek open-plan, purpose-built converted factory, sip-ping on unlimited free Ribena cartons. Plants and plasma screens dot the space. A large board full of neatly arranged Post-it notes, showing the company's production schedule, occupies one wall. Rocksteady employees work hard. 'During projects, we do incredibly long hours, for a very long time,' says Walker, 40. The 'crunch' for Arkham City lasted about eight months, with people working until 11 or 12 each night, with an 8am start. 'When I started working in the industry 20 years ago,' he goes on, 'you used to work until three or four in the morning, then roll in at ten the next day. We're a bit more professional now.' Rocksteady doesn't allow its employees access to the internet during the day ('culturally quite a shock,' says Walker) and has created a scheduling system to monitor each designer's progress: 'If you haven't done the task, the system knows and lets your manager know.' The idea isn't to terrify employees into activity, he says, but to let managers know what's holding up the process. The system also measures employees' happiness, asking them to rate how content they are out of ten each week. It sounds intense, but only seven people have left the company of their own accord in seven years.