Sonic the Hedgehog may easily outrun a spring chicken, but he's not exactly "young" anymore. The blue dash turns 20 this year, having only lost weight with age; and to celebrate the big two zero, Sega is releasing Sonic Generations for Xbox 360 and PlayStation 3. It's a full price retail game, coming this holiday, that pays homage to the storied history of Mr. the Hedgehog.

Late last week I played through the first level of Sonic's cross-generational platformer on Xbox 360 -- a "reimagining" of Sonic's Green Hill Zone -- using both old (chubby) and new (skinny) Sonic. Here's how the pairing works: each level of Sonic Generations is playable with either character, and both offer different routes and perspectives.