

The first version of the system sat under the Genesis console and loaded CDs via a motorized tray. This posed a problem in the markets outside of Japan, where the PC Engine did not fare very well, and the expectation was that the Mega-CD would be in competition with Nintendo. The Sega CD was not meant to compete with the Super Nintendo. The Sega CD was designed to compete with the TurboGrafx-16 PC Engine (TurboGrafx-16) in Japan, which had a separate CD-ROM drive.

The development of the Sega CD was confidential game developers were not made aware of what exactly they were working on until the add-on was finally revealed at the Tokyo Toy Show in Japan.

The system allowed the user to play games, audio CDs, and CD+G CDs. The Mega-CD (メガCD), also known as the Sega CD, is an add-on device for the Mega Drive released in Europe, Australia, New Zealand, North America, and Japan.
