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 the Hedgehog 2
Sega launched a $10 million advertising campaign for "Sonic the Hedgehog 2"s release. Sega sought a global release date to make the game available in all stores on the same day, a fairly novel concept at the time. This required Sega to reconfigure its distribution system to ensure that games were available in all major stores. The release date, Tuesday, November 24, 1992 was marketed as "Sonic 2s day". While the Genesis release in North America and the Mega Drive release in Europe both released the game on this day, Sega made the game available a few days before in Japan on November 21, 1992. 400,000 copies of "Sonic 2" were sold in the first seven days after release and over 6 million in the lifespan of the console (only 180,000 of which were in Japan).