When Microsoft announced earlier this year that Double Fine would be making a Kinect-based Sesame Street game, many wondered if the developer studio behind Psychonauts and Brutal Legend were leaving their own original ideas behind for a lucrative licence. But Nathan Martz, project lead on Sesame Street: Once Upon A Monster, says that it was just the opposite. The game that became Once Upon A Monster actually started internally at Double Fine as an independent project. That fact and more came to light when I e-mailed Martz some questions about the creation of the new Sesame Street game. He discusses how he and his Double Fine colleagues came to grips with creating a game that would star some of the most recognisable characters in the world and why even the worst kids’ video games are triumphs of a sort.