One of the defining things about the development of Duke Nukem Forever (DNF) was the often interminable wait between any information about the game. It really is depressing to realise that DNF started life using the Quake II engine, which seems so incredibly primitive in an age of CryEngine and Unreal Engine 3. It then swapped to Unreal, then the Unreal Tournament codebase, then allegedly an in-house engine, before landing back on a modified Unreal engine.
This, alone, provides a fascinating look into the evolution of 3D gaming. The trailers and screenshots released over the years often show the same areas in vastly different ways. What is most fascinating now was that each time new screens were released, they showed cutting edge visuals for the time. In hindsight, the low polygon counts, over-dramatic lens flare, simplistic environments, and low-res textures of the early shots look bad – but they serve to illustrate just how much has happened in the meantime.