Here's a magnificent grid showing how a humble rock would be displayed by an enormous variety of video games' rendering engines, executed with affection and wit (Fipi Lele pointed out that the Zork version would be, "There is a rock here."). The rock is the perfect, Sluggo/Zippy-esque subject for this kind of comparison, absolutely bang-on.
All I know about this image is that Kotaku apparently published it in April, 2006. Oh, and that it rocks. So to speak.
(Thanks, Fipi Lele!)