While Doom can sometimes feel like an overnight smash success, the seminal first-person shooter was far from the first game created by id co-founders John Carmack and John Romero. Now, in a rare joint interview that was livestreamed during last weekend's 30th-anniversary celebration, the pair waxed philosophical about how Doom struck a perfect balance between technology and simplicity that they hadn't been able to capture previously and have struggled to recapture since.