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 Mania
In addition to the standard release, a Sega Genesis-themed collector's edition was also released, containing a 12-inch (30 cm) Sonic statue atop a model Genesis, a game cartridge cast with a golden ring, and a metallic collector's card with a download code for the game. To promote the collector's edition, Sega released a retro-styled infomercial featuring former series art director Kazuyuki Hoshino and social media manager Aaron Webber, based on an American television commercial for "Sonic 2". The music label Data Discs published a vinyl LP featuring the game's original music in late 2017. An expanded soundtrack was released on digital music distribution platforms on January 17, 2018.