Sonic CD

Sonic CD, also known as Sonic the Hedgehog CD, is a 1993 platform game developed and published by Sega for the Sega CD. As Sonic the Hedgehog, the player attempts to protect an extraterrestrial body, Little Planet, from Doctor Robotnik. Like other Sonic games, Sonic runs through themed levels while collecting rings and defeating robots. Sonic CD introduces time travel as a game mechanic. By traveling through time, players can access different versions of stages, featuring alternative layouts, music, and graphics. Sonic CD introduced the characters Amy Rose and Metal Sonic.

Sonic CD began as a port of the Sega Genesis game Sonic the Hedgehog (1991), but developed into a separate project. Led by Sonic's co-creator Naoto Ohshima, the developers sought to showcase the technical capabilities of the Sega CD, with animated cutscenes by and Studio Junio and Toei Animation and CD-quality music. The soundtrack, influenced by house and techno, was composed by Naofumi Hataya and Masafumi Ogata. For North America, a new soundtrack was composed by Spencer Nilsen, David Young, and Sterling Crew.

Sonic CD was released in late 1993. It received acclaim and is often regarded as one of the best Sonic games and also one of the best video games of all time. Reviewers praised its size, music, and time travel feature, although some felt it did not fully use the Sega CD's capabilities. It sold over 1.5 million copies, making it the best-selling Sega CD game. Sonic CD was ported to Windows in 1996 and to the PlayStation 2 and GameCube as part of Sonic Gems Collection in 2005. A remake, developed by Christian Whitehead using the Retro Engine, was released for various platforms in 2011 and as part of the Sonic Origins compilation in 2022.