Though portable gaming platforms existed as early as the 1976's Auto Race from Mattel, handheld gaming was largely an untapped market prior to 1989. Aside from Nintendo's own Game & Watch series, the main handheld of note before the Game Boy was Milton Bradley's Microvision, which featured interchangable cartridges as early as 1979. However, even the Microvision was fairly insignificant, with only 12 games ever released.
The dedicated handheld gaming market was pioneered by the Game Boy, which in turn was the brainchild of Gunpei Yokoi. Yokoi had joined Nintendo back in the 1960's, and by the 80's was one of the chief creative minds at the company. His Game & Watch series of handheld games, of which 60 were released from 1980 to 1991, sold a total of over 43 million units total. Though these games featured technology scarcely more complicated than that in a pocket calculator, Gunpei Yokoi still created innovations such as the D-Pad and multiple screen use, which would be highly influential on future hardware.
The Game Boy itself started development in 1987, with Yokoi leading the design of the new hardware. He was assissted by Satoru Okada, who would lead the development of the Game Boy Advance and Nintendo DS years later. The goal was to create a handheld that would cost under 13,000 yen, or roughly $200 in 2015 US Dollars.
To keep under the maximum price, Yokoi and Okada made a number of concessions to the Game Boy's specifications. Although its CPU was actually a touch stronger than the Famicom's, the screen would only display four shades of color, based on green and black. There was no lighting included. Fortunately, this meant that the battery life was an impressive 35 hours from 4 AA batteries.
The Game Boy's controls were virtually identical to the NES's with a D-Pad, pair of face buttons, and pair of menu buttons. Headphones allowed for stereo sound. The most notable peripheral was the Link Cable, which connected Game Boy units for multiplayer.
Hardware aside though, it was clear that the Game Boy would require acclaimed software to be successful. Nintendo approached this challenge from multiple fronts. First, Nintendo R&D 1 developed Super Mario Land as a companion to the popular Famicom games. With series creator Shigeru Miyamoto focusing on the upcoming Super Famicom's launch titles, it fell to Gunpei Yokoi and Satoru Okada to lead the creation of this new game. The result was a different game than prior Super Mario entries, and one that was far more anemic to the then-new Super Mario Bros 3. However, it was successful at creating a handheld incarnation of a console-based series.
The true star of the Game Boy's launch line up would actually be something completely different from Mario: the puzzle game Tetris. Tetris was first created in 1984 by Alexey Pajitnov at the Academy of Science in the USSR. In the following few years, it filtered first into eastern Europe and soon across the world. By 1989, versions of Tetris had appeared on a number of platforms from multiple developers. Nintendo would be the first company to directly obtain rights to the property, giving the Game Boy a second and even greater killer app.
The Game Boy was released in Japan on April 21, 1989. American and European launches would follow on July 31, 1989 and September 28, 1990. Super Masrio Land was available at launch in all regions, but Tetris was frequently bundled in the Western launches. Other launch titles in various regions included Alleyway, Baseball, and Tennis. The US launch price was $89.99.
The Game Boy had a very successful launch. In Japan, the intial shipment of 300,000 units was sold out in two weeks. In America, 40,000 units were sold the first day.
