Tetris (Sega Genesis/Mega Drive)

Everyone remembers Tetris, the classic puzzle game. Due to confusion over licensing issues and Nintendo securing exclusive rights to "Tetris" on video game consoles, the Sega Genesis (or Mega Drive) never saw its planned "Tetris" game, which was based on Sega's Japanese arcade version, released. The unlicensed version was recently confirmed to exist by none other than "Tetris" creator, Alexy Pajitnov (right). RacketBoy estimates around 10 copies of "Tetris" for Sega Genesis exist today.