The Sega Mega-CD was released first in Japan in 12th December 1991 followed on October 15th 1992 and April 1993 in Europe

The Sega Mega-CD is an add-on device for the Sega Mega Drive released in Europe, Australia, and Japan. The North American version is called the Sega CD. The device allows the user to both play CD audio discs and specially designed game CDs.

At first, the Sega CD was a CD tray unit that sat under the console. The Sega CD 2 was a smaller, cheaper top loading drive that plugged next to the Sega Mega Drive.

Initially, it was a great success because of the inherent advantages of CDs (high storage capacity and the low cost of media). The fact that it had a nice RPG catalogue also helped.

A lot of the Sega Mega CD library was made up of upgrades of existing Megadrive/Genesis games. Most of them had some extra FMV scenes and an enhanced soundtrack, but the game remained mostly unchanged. However, some games such as Earthworm Jim or Spider Man vs. the Kingpin added some extra levels or made some  large game changes.  The console's flagship title was a Sonic game, titled Sonic CD. While the game is highly regarded, the CD platform offered little difference in the way of game play, but displayed a lot advantages of a CD based system, these include animated cut scenes, a high quality Redbook audio soundtrack, and a  larger amount of content (i.e. levels, characters etc) . The Sega CD also had the Lunar series, which received two titles on the Sega CD, that went on to be critically acclaimed and became a cult classics.