A recent comment* on this site, and I’d like to quickly point out how comments can translate into more content for you, the coffee drinker, to read, has led me to realize that there is, without question, a fifth category. And in essence, isn’t this really the original category? This was when games were just games, when there were no categories or genres.
Pixels! Let us toast to pixels! Polygons be damned!
* for further enlightenment, visit http://ieatgames.wordpress.com