As the term "video game" implies, visual information is very important to the media.
Until the mid-1990s, most game graphics were two-dimensional. When more powerful machines and graphic software made the possibility of three-dimensional graphics practical, this became the new trend. Some games are a hybrid of the two techniques, and they are called two-and-a-half-dimensional. One-dimensional games are stupid, and four-dimensional games are currently impossible (philosophical discussion of the nature of the fourth dimension aside).
Many modern developers - almost everyone except EA - are agreeing that graphics have been the driving force of game hardware for long enough, and new graphical innovations are no longer sufficient to carry the industry. Nintendo is spearheading a campaign of design innovation without powerful graphics with its Wii and DS, and it will probably be interesting to see how this turns out.