1up has up a piece on Handheld Heroes
, portable games that have (despite their small size) make herculean changes in the face of gaming as a whole. From the article: "Tetris is, quite possibly, the most important portable game of all. While the drama surrounding its NES incarnation gets the most attention, the Game Boy version quietly sold millions and millions of handheld systems to people who were instantly addicted to its simple, intuitive, challenging gameplay. It's no exaggeration to say that Tetris single-handedly created the portable market, helped the Game Boy conquer its competition, and gave Nintendo an enduring source of income that's still going strong."