SEGA have announced they're re-releasing their Sonic Generations demo, this time with Green Hill Zone's modern stage accessable. That means potential customers who haven't had a chance to get to trade shows and expos can get their first taste of the Blue Blur's modern levels.
The demo will be available on consoles from October 25th, so you've got about a week to wait.
I played the City Escape levels at Eurogamer last month, I was very impressed in how they'd took the best of the original and transformed it into something new. I remember being disappointed by the 2D Green Hill Zone but, in hindsight, it may just have been because it was quite different from Sonic 4, which I'd been playing quite a lot at the time.
If you're already convinced that you need to buy Sonic Generations and you're not bothered by little things like demoes, you need only wait until the beginning of November, it comes out on the 1st in America.