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 the final "Sonic the Hedgehog" game produced for the Sega Genesis, and was developed as a swan song for the system. Sega had discontinued official support for the Genesis in 1995, but intended to produce the game for the 16-bit console because games typically sell for one to two years after their platforms' discontinuation. The game's basic concept was conceived by members of Sonic Team during the development of "Sonic the Hedgehog 3", but most of the programming was done by the British studio Traveller's Tales because Sonic Team was developing "Nights into Dreams". According to founder Jon Burton, Traveller's Tales had just finished developing a "Toy Story" game and wanted to start developing games for 32-bit systems such as the Saturn and PlayStation. Sega, impressed with their work on "Toy Story" and "Mickey Mania", approached them with "3D Blast"; as "Sonic" was extremely popular at the time, the concept "got [their] attention". In retrospect, Burton stated that he believed the game was commissioned because "Sonic X-treme", in development for the Saturn at the time, was struggling, and Sega wanted to bring Sonic into the 3D era of gaming.