Nintendo's 1989 handheld system that used interchangeable Game Paks was the Game Boy.
Nintendo launched the Game Boy in Japan on April 21, 1989, followed by North America and Europe later that year. Designed by Gunpei Yokoi and Nintendo's R&D1 team, it used removable cartridges called Game Paks.
The monochrome system had less powerful hardware and a simpler display than rivals such as the Sega Game Gear and Atari Lynx. Its long battery life, compact design, recognizable controls, and strong software library helped it become a major commercial success.
Tetris was bundled with the Game Boy in many markets, making the handheld attractive to people who had never owned a game system. The later Game Boy Color added color graphics while remaining compatible with much of the original library.