Sonic the Hedgehog CD (ソニック・ザ・ヘッジホッグCD, Sonikku za Hejjihoggu Shīdī?), or simply Sonic CD, is a platform game in the Sonic the Hedgehog series, developed by a different division at Sega rather than Sonic Team. It marked the first official appearance of both Metal Sonic and Amy Rose. It was released for the Sega Mega-CD in Japan on September 23, 1993, in Europe in October, 1993, and finally for the Sega CD in North America on November 19, 1993. The game was ported to PC CD-ROM in 1996.
It was also on the GameCube (as part of Sonic Gems Collection) and PlayStation 2 (as part of Sonic Gems Collection)
an extended description!