While some companies seem to hate giving their loyal customers nifty bonuses nowadays, others seem to like doing the opposite. After several rumors, Sega has confirmed that the Xbox 360 and PlayStation 3 versions of Sonic Generations will feature the game that started it all as an unlockable feature.
Completing levels and tasks in-game awards the player points. The player may then spend these points in the game’s Skill Shop. One item players can purchase is called the “Sega Genesis Controller”; when used, players will be presented with a playable, full version of Sonic the Hedgehog, originally released for the Sega Genesis (Or Mega Drive, depending on what region you live in) in 1991. Additionally, points can be used to unlock infinite lives in the original game.
Sonic Generations is set to be released on November 1 for the Xbox 360 and PlayStation 3 in North America.
Source: SEGA Blog