There is a (somewhat lengthy) article over at Gamasutra about level design. The article focuses solely on the evolution of first person shooters, but is nevertheless a good read. It’s a pretty good chronicle of the progress that has been made in computer graphics over the years. Some of the key games mentioned include Doom, System Shock, Duke Nukiem 3D, and of course Half-Life. The article details how each successive game added new features and graphical/physical capabilities. Of all the great features that have been put into games over the last 15 years, it fails to mention the greatest feature of all: giving money to strippers in Duke Nukem 3D.
Be warned, this is an academic paper, citations and all. It has more than a few typos, too—do they not have editors at Gamasutra? You can find the article here: