In case the classic Sonic the Hedgehog gameplay isn't classic enough for you in Sonic Generations, Sega's tucked an old school surprise in the PlayStation 3 and Xbox 360 versions of next week's hedgehog revival.
Completing levels in Sonic Generations earns players points in the game's Skill Shop. One of the items up for sale in said shop is a Sega Genesis controller. Purchase it, and you'll gain access to the original Sonic the Hedgehog adventure that started this whole mess in the first place. Even better (for you dirty cheaters), you can also purchase infinite lives in the original game, giving those that never finished the first one a sporting chance at doing so.
And if you've never completed the original Sonic the Hedgehog, please don't tell us that. We'd rather remember you as you are now, before you ruined everything.