Details are still sketchy but one thing is clear: the original Sonic game will be an unlockable in Sonic Generations. We’re not sure yet if this only applies to the console and PC versions, which leaves the 3DS out of luck.
Takashi Iizuka of Sonic Team announced this news at a panel in France during Paris Game Week. It was not announced how it will be unlocked but it is a nice little extra to have for those who haven’t already bought Sonic on XBLA, PsN, Vitural Console, iPod Touch and the eleven-odd-some other systems that Sonic has been released on since 1991.
If you haven’t already, check out the demo for Sonic Generations, where you can take control of retro/classic Sonic and modern Sonic.