Sonic the Hedgehog
The Sega Genesis had "add-on" systems that incorporated "Sonic" games. "Sonic CD", released for the Sega CD, was a 2D platform game released in 1993. The game introduced the characters Amy Rose and Metal Sonic and featured levels that differed depending upon whether Sonic was in the past, present, or future time frames. "Knuckles' Chaotix", a spin-off released in 1995 for the Sega 32X, featured Knuckles and a new group named Chaotix fighting against Dr. Robotnik. The game featured a two-player cooperative system in which the on-screen characters were connected by magic rings. There was also "Sonic Eraser", a puzzle game released exclusively on Sega Game Toshokan in 1991.
Sonic 3D Blast
"Sonic 3D Blast" was released for the Genesis in Europe on November 5, 1996, and the North American version was released on November 7, 1996. The Saturn version was released in Europe on February 13, 1997. The Genesis version was not released in Japan; only the Saturn port was, on October 14, 1999. A port of the Sega Saturn version was released for Microsoft Windows in Europe on September 11, 1997, and worldwide later that year. The game's launch coincided with the release of the similarly-titled Game Gear game "Sonic Blast", which also features pre-rendered 3D graphics.