A virus is a microscopic organism that can replicate only inside the cells of a host organism. Most viruses are so tiny they are only observable with at least a conventional optical microscope.
Recognized by the Guiness Book of World Records as the MMO with the longest play time per player, and easily the oldest game on this list (launching four years ahead of World of Warcraft, way back in 2001), Runescape deserves mention because it's one of the most updated and popular games of any kind on the planet.
The 10 Longest Games Ever - NowGamer. NowGamer looks at the longest games in different genres, from the longest FPS games, to the largest open worlds. This is a list of longest games by genre, NOT longest games full stop. Culture Demon's Souls Disgaea Final Fantasy XII Grand Theft Auto: San Andreas Half-Life 2 Just Cause 2 nowgamer.com.