Thanks to Pat for posting this on Facebook and bringing it to my attention. This shows much more than the original teasor trailer. Sonic Generations is a new retail Sonic game recently announced in which you can play as the classic, pudgy Sonic or the modern streamlined Sonic.
In the classic gameplay (the first half of the video), the game is a side-scrolling platformer all about speed and looks like the classic games. The modern Sonic gameplay switches between side-scrolling and the behind-Sonic camera found in games like Sonic and the Secret Rings and the daylight Sonic Unleashed stages. The modern gameplay also features dashes and homing attacks while the classic does not.
Also, it’s noteworthy that in this extended trailer, you see Sonic for the most part keeping his speed. He sometimes must wait for platforms, but it seems like he’s usually able to keep running forward when played correctly. At least Sega realizes what’s the game supposed to be. I hope Sonic Generations is good.