From Wikipedia:
Dragon Warrior I & II for the Game Boy Color was originally published in Japan on September 23, 1999 as Dragon Quest I & II. It was then localized in English for publication in the North American market on September 27, 2000.
It is a single game cartridge compiling Dragon Quest I and Dragon Quest II from the Dragon Quest series. Both of the games collected here were originally developed and published for the Famicom (known internationally as the Nintendo Entertainment System) and later ported to MSX computers.
The Game Boy Color remake was based on an earlier Dragon Quest I & II remake for the Super Famicom (SFC, the Japanese version of the Super NES), which was marketed exclusively in Japan in December 1993, due to the closure of Enix America Corporation, but was since unofficially translated into English in 2002. This game was given upgrades based on the Dragon Quest V game engine, which was released in 1992. The Super Famicom remake is the first such remake of any Dragon Quest game on a different console, with enhancements. This paved the way for many future updates for other games in this series.
