Interview: John Carmack and Tom Mustaine on Doom, iPhone Desires, and the Future of id Mobile is a conversation about the just-released DOOM Resurrection for iPhone as well as id Software's ambitious mobile gaming plans. According to Tom, they started using touch screen controls, and the project may well have been cancelled until they found its fun factor in the accelerometer: "So we made a pretty big change. At the halfway point of the project we were kind of considering, this could get canceled if it doesn't get fun. And so we moved it over to the accelerometer controls, and it was kind of surprising, because I think we've played almost every other game called a shooter on the iPhone, and nobody's really landed on this control mechanism before. And that was kind of our 'ah-ha' moment."