The Sega CD, also known as the Sega Mega CD, Add-on to the Sega Genesis was released in 1991 in Japan and in 1992 in North America. Not meant to compete against the Super Nintendo, the Sega CD was made for competition against the PC Engine, a major rival in Japan.
Two Sega CD systems were released in the United States, the original, a CD Tray unit which sat under the Sega Genesis, and a the second model, a smaller, top loading drive which plugged into the side of the Sega Genesis.
While the Sega CD only had 143 games released for the system, true classics were released such as: Lunar: The Silver Star Story, Lunar 2: Eternal Blue, and Popful Mail by Working Designs, Keio Flying Squadron, Lords of Thunder, Road Avenger and Time Gal.
Road Avenger and Time Gal are arguably the greatest full-motion video games. Snatcher, also released on the Sega CD is one of Hideo Kojima, of Metal Gear fame, first published games. The Sega CD was also home for Sonic CD, one of the greatest Sonic games ever made.