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.
Sonic Mega Collection
"Sonic Mega Collection" features twelve to fourteen complete games in one retail unit. All games are ports of their original versions on the Sega Genesis. High-resolution instruction manual scans are included for each game. Also included is an "Extras" section featuring over 100 scans of "Sonic the Hedgehog" comic covers, illustrations of "Sonic" characters throughout the franchise's history, and a handful of videos promoting other "Sonic" games, including the beginning and end sequences to "Sonic CD". In addition to the seven default games, three unlockable games are included that recreated the "Sonic & Knuckles" "lock-on technology" by allowing players access to new gameplay features and special stages by opening the hatch of the "Sonic & Knuckles" Sega Genesis cartridge and inserting another compatible cartridge, in this case each of the first three games in the "Sonic the Hedgehog" series. Also, four games published by Sega but not in the "Sonic" series could also be unlocked (two in the North American version).