The Game Boy is Nintendo's second handheld system following the Game & Watch series introduced in 1980, and it combined features from both the Nintendo Entertainment System and Game & Watch. It was originally bundled with the puzzle game Tetris.
As part of the fourth generation of gaming, the Game Boy competed with the Sega Game Gear, Atari Lynx, and the TurboExpress. Despite these other handheld consoles, the Game Boy was a tremendous success. The Game Boy and its successor, the Game Boy Color, have both combined sold 118.69 million units worldwide. Upon its release in the United States, it sold its entire shipment of one million units within a few weeks.