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.
List of Sega Saturn games
Development of the Saturn began in 1992, the same year Sega's groundbreaking 3D Model 1 arcade hardware debuted. Designed around a new CPU from Japanese electronics company Hitachi, another video display processor was incorporated into the system's design in early 1994 to better compete with Sony's forthcoming PlayStation. The Saturn was initially successful in Japan, but failed to sell in large numbers in the United States after its surprise May 1995 launch, four months before its scheduled release date. After the debut of the Nintendo 64 in late 1996, the Saturn rapidly lost market share in the U.S., where it was discontinued in 1998. Having sold 9.26 million units worldwide, the Saturn is considered a commercial failure. The failure of Sega's development teams to release a game in the "Sonic the Hedgehog" series, known in development as "Sonic X-treme", has been considered a factor in the console's poor performance.