Sega’s launched the demo of Sonic Generations for Xbox Live Marketplace.
You can queue it to your console here. It’s a Gold exclusive which comes in at 652Mb. You’ll try out the first act from the Green Hill Zone as Chubby Sonic, apparently.
Its also gone up on the EU PS Store. It comes it at 664Mb.
The demo release is part of Sonic’s 20th anniversary, which is happening today.
Full game’s out later this year.