Edited sentence: Anonymous commentary by ex-3D Realms employees seems to confirm this, for example Broussard would demand that small sections of the game's levels be recreated over and over changing the most minute details, till he was satisfied with that levels gameplay and visuals.Essentially, it appears that not only is the games code revised and content updated every three years or so, but also the design of the game is transformed from version to version.The reason for this appears to be Broussards extreme and pedantic level of perfectionism - the games are scrapped because they do not conform to some kind of quality standard