The Sega CD, released as the Mega-CD in most regions outside North America and Brazil, is a CD-ROM accessory for the Sega Genesis produced by Sega as part of the fourth generation of video game consoles. It was released on December 12, 1991, in Japan, October 15, 1992, in North America, and April 2, 1993, in Europe. The Sega CD plays CD games and adds hardware functionality such as a faster CPU and graphic enhancements such as sprite scaling and rotation. It can also play audio CDs and CD+G discs.
Sega sought to match the capabilities of the competing PC Engine CD-ROM² System, and added an additional CPU and custom graphics chip. They partnered with JVC to design the Sega CD. Fearful of leaks, Sega refused to consult with Sega of America until the project was complete; Sega of America assembled parts from dummy units to obtain a functioning unit. The Sega CD was redesigned several times by Sega and licensed third-party developers.
The main benefit of CD technology at the time was greater storage; CDs offered more than 320 times more space than Genesis cartridges. This benefit manifested as full-motion video (FMV) games such as the controversial Night Trap, which became a focus of the 1993 congressional hearings on issues of video game violence and ratings.
The Sega CD game library featured acclaimed games such as Sonic CD, Lunar: The Silver Star, Lunar: Eternal Blue, Popful Mail, and Snatcher, but also many Genesis ports and poorly received FMV games. The high price of the Sega CD was also a contributing factor in its lack of success. Only 2.24 million Sega CD units were sold, after which Sega discontinued it to focus on the Sega Saturn. Retrospective reception is mixed, with praise for some games and functions, but criticism for its dearth of deep games, high price, and lack of support from Sega. Sega's poor support for the Sega CD has been criticized as the beginning of the devaluation of its brand.