Sonic the Hedgehog
Due to the success of "Sonic" games on the Sega Genesis, the series was introduced to the Master System and the Game Gear. Sega began by releasing "Sonic the Hedgehog", a 2D platform game, in 1991. The game featured Sonic's ability to run and to jump at high speeds like its Mega Drive/Genesis counterpart but with notably different level design and music. Sega later released "Sonic the Hedgehog 2" another 2D platform game, in 1992. The game differed from its Genesis counterpart with different levels and music and by not including a "spin dash" maneuver. It also featured a different storyline in which Doctor Robotnik kidnaps Tails, who is non-playable in the Master System/Game Gear version. "Sonic Chaos"/"Sonic and Tails" (Japan), released in 1993, was similar to the earlier two Sega Master System/Game Gear "Sonic" games, but featured Tails as a playable character. A sequel, "Sonic Triple Trouble"/"Sonic and Tails 2" (Japan), a 2D platform game, was released in 1994 for the Game Gear and introduced a new character, Nack the Weasel, who, along with Knuckles and Doctor Robotnik, raced to collect the Chaos Emeralds. One of the last games for the Sega Game Gear, "Sonic Blast", was released in 1996 and featured prerendered sprites.
List of Sega CD games
The Sega CD, originally released as the in most regions outside of North America and Brazil, is an add-on device for the Sega Genesis video game console, designed and produced by Sega. It was released in Japan in 1991, North America in 1992 and in PAL regions in 1993. The device adds a CD-ROM drive to the console, allowing the user to play CD-based games and providing additional hardware functionality. It can also play audio CDs and CD+G discs. While the add-on did contain a faster central processing unit than the Genesis, as well as some enhanced graphics capabilities, the main focus of the device was to expand the size of games. Known for several games such as "Sonic CD" and for the controversy of violent video games including "Night Trap", the Sega CD sold 2.24 million units worldwide. It was officially discontinued in 1996.