In a special presentation, Alex Battaglia takes a look at Doom past and present, discussing the massive technological leap delivered by John Carmack back in 1993 - and the vastly expensive technology required to get playable frame-rates - through to the extra scope and demands of Doom 2 and the incredible per-pixel lighting of Doom 3. It's a series defined by technological innovation pushing PC hard - as exemplified by our final game in focus - Doom: The Dark Ages.