Nintendo · 1994 · Super Nintendo / Super Famicom
A SNES cartridge with a Game Boy inside it — not an emulator but the actual handheld hardware, playing monochrome carts on a television with colour palettes and decorative borders.
The Super Game Boy is a SNES cartridge containing genuine Game Boy hardware. The SNES does not emulate anything; it supplies power and a clock, receives video and audio from the Game Boy silicon inside the cartridge, and paints the result on a television. This architectural honesty is why compatibility was essentially perfect — a game running on a Super Game Boy is running on a Game Boy, on a slightly faster clock. That clock is the accessory's best-known quirk. Because timing is derived from the SNES rather than from the handheld's own crystal, everything runs roughly 2.4% fast: music plays a shade sharp and games are marginally quicker than on hardware. The adapter added a four-colour palette selector, applied to a monochrome game's four shades, and a decorative border to fill the area of the screen the Game Boy's 160×144 image could not. Developers who cared could do considerably better than the defaults. A cartridge could carry Super Game Boy enhancement data specifying its own palettes, its own custom border artwork, and in some cases additional audio played through the SNES rather than the Game Boy's sound hardware — which is why Donkey Kong (1994), Kirby's Dream Land 2 and the Pokémon games look and sound conspicuously better through the adapter than the palette menu alone would allow. The conspicuous omission was the link cable. The original Super Game Boy has no link port, so the trading and battling that defined the platform's biggest games were impossible through it. Nintendo addressed this with the Super Game Boy 2, released in Japan in 1998, which added a link connector and corrected the clock to the handheld's true speed. It never left Japan, which means that for the entire Western life of the accessory the definitive Game Boy social features were the one thing the television version could not do.