The first Pokemon game! Along with Pokemon Red, those two versions were released in Japan in 1996 and started a franchise, that lives and thrives to this day! Pokemon Green/Red also proved that you don't need powerfull and shiny graphics to be successful - these games were really unpolished on their release, containing many bugs (which, ironically, made them all that more interesting) and frustrating, untested mechanics, but they were based on a brilliant, innovative idea that caught on and spawned a tons of sequels and spin offs. Definitely a game that every gamer should play.