Enlarge (credit: Aurich Lawson | Id | GDC)

John Romero remembers the moment he realized what the future of gaming would look like.

In late 1991, Romero and his colleagues at id Software had just released Catacomb 3-D, a crude-looking, EGA-colored first-person shooter that was nonetheless revolutionary compared to other first-person games of the time. "When we started making our 3D games, the only 3D games out there were nothing like ours," Romero told Ars in a recent interview. "They were lockstep, going through a maze, do a 90-degree turn, that kind of thing."

Despite Catacomb 3-D's technological advances in first-person perspective, though, Romero remembers the team at id followed its release by going to work on the next entry in the long-running Commander Keen series of 2D platform games. But as that process moved forward, Romero told Ars that something didn't feel right.