According to John Romero, id Software's design documentation was minimal and often not written down formally. The creative director served as the living design document, and the team would discuss and agree on the game's direction. This approach was possible because games were smaller in scope, allowing for a more straightforward development process.
Id Software's development process in the early 1990s was unique due to its focus on speed, both in gameplay and development. The team prioritized simple rendering and high-speed gameplay, which differentiated their games from other 3D experiments at the time. They also didn't use design documents or version control systems, instead working compartmentalized and directly with each other on their respective tasks.
Romero described the 3D games existing before Catacomb 3-D as "lockstep" and involving "going through a maze, do a 90-degree turn, that kind of thing." He emphasized that they were very different from what his team at id Software was working on at the time.