The SNES cartridge – which allows you to play Game Boy games on your TV with added color and special borders – launched in Japan on June 14th, 1994 (thanks, Tokyo Game Life). It would come to North America and Europe in the same month.
In addition to the obvious benefit of allowing you to play your Game Boy games on the big screen (and with added color), the Super Game Boy allowed certain titles to make use of the SNES hardware for bonus features.
For example, some games had improved sound, while titles like Killer Instinct made use of the Super Game Boy to offer a two-player option (something that was only possible on the Game Boy when using a link cable, two consoles and two copies of the game). Others had unique borders which would surround the main screen.
Certain games got even more creative with the device; for example, the Game Boy version of Space Invaders includes the SNES version of the game on the same cartridge.
Nintendo would follow up with the Super Game Boy 2, which launched in Japan in 1998. This device included a link port for link cable play, among other features. It was never released worldwide.
