Chaos emeraldsOf all the Sonic games, Sonic the Hedgehog is the only game to have only 6 Chaos Emeralds. Every other game in the series features 7 Emeralds.
CompilationsSonic the Hedgehog was included on compilations for many platforms, including Sega Smash Pack: Volume 1 for Dreamcast, Sonic Mega Collection for Gamecube and Sonic Mega Collection Plus for Xbox, PlayStation 2 and Windows.
Creation of Sonic
DevelopmentIn many early screenshots of the Marble Zone, there are UFO-like objects floating in the sky. Footage of a prototype Marble Zone (complete with UFOs) is shown during a commercial in the movie Wayne's World. No one knows what the objects were for, or why they were removed.
Dreams Come TrueThe Japanese rock group Dreams Come True, who also composed all of the music for Sonic the Hedgehog (as well as Sonic 2 and Sonic CD), also helped promote Sonic in Japan! During one major tour they took across Japan in the summer of 1991, they had murals of Sonic painted onto the trucks that carried their equipment to get the people's attention. And then to make it even better, their song "Sweet Sweet Dream" was chosen to be the ending theme for Sonic 2!
Dr. EggmanDr. Eggman's name was changed to Dr. Ivo Robotnik for all English language versions. He would retain this name for all his English language appearances right up until Sonic Adventure , when it was intentionally phased out and restored to Dr. Eggman, presumably because that game heralded Sonic's return to glory and there was a desire for him to return to his roots. However, the Robotnik name was officially acknowledged in Sonic Adventure 2 , even in the Japanese continuum.
Formula 1 sponsorshipWith sponsorship from SEGA, Sonic appeared on the Williams Formula 1 team in 1993. The hedgehog could be seen on the drivers' cars, and their helmets. Their rival team McLaren would often paint a squashed Sonic on their drivers' helmets after winning a race against Williams. Williams, however, would have the last laugh, when their team leader Alain Prost, secured the drivers' championship, and with the help of Damon Hill, the constructors' championship for 1993.
Game Boy Advance versionThe 2006 GBA release is a port of the Genesis version. It includes a new save system and the Anniversary Mode, where the spin dash (a feature that enables Sonic to roll into a ball and rev up a spin attack from a dead stop, not available in the original game) has been added.
Japanese versionCuriously, though the game was developed entirely in Japan, Sonic the Hedgehog was first released in North America and Europe, with the Japanese release coming a month later. The Japanese version features several bug fixes and visual effects that didn't make it into the initial international release. In particular, the infamous "spike bug" (where if Sonic hits spikes, and the hit knocks him into another set of spikes, he dies immediately even though he should still be invulnerable) is fixed. The parallax scrolling in the background of many zones is enhanced, and there are additional water effects in Labyrinth Zone.
Mobile versionThe mobile edition is ported from the Genesis version. In Europe, the game was not released as a whole, but in two individual parts: Sonic the Hedgehog Part 1 and Sonic the Hedgehog Part 2.
Android releaseIn the beginning menu, the original Mega Drive case is displayed; original game cartridge is too, when tapping to start a game. An option allows choice on viewing Japanese, United States, or European case and cartridge.
SalesThe original Sonic The Hedgehog game for Sega Genesis sold 4 million units worldwide. As of 2003 the whole Sonic series (for all consoles) sold over 27 million units since its first release in 1991.
Scrap Brain ZoneThe Scrap Brain Zone was originally called the Clock Work Zone.
Additional information contributed by 雷堂承太朗 -djsw-, Ace of Sevens, Big John WV, DOS Boot, Marguerite Richardson, MegaMegaMan, Mumm-Ra, PCGamer77, Robbb and Sciere.
Contributed by Satoshi Kunsai (1817) on Jun 07, 2002. [revised by : ^~…±‰≈≠¤ (MobygamesIsDead) (582) and Patrick Bregger (98698)]. -- edit trivia