Video: Sonic the Hedgehog 4 Gameplay
From what the leaked video shows, Sonic 4's Episode 1 will consist of the following 5 levels:
Splash Hill Zone, Lost Labyrinth Zone, Casino Street Zone, Mad Gear Zone, and a Special Stage
The gameplay itself looks a bit rough, as in not finished, so don't take this in yet as the final product, but I can't shake the fact that Sonic doesn't seem to move the way he used to. I'm not sure how to put my finger on it, but there's something off about how he picks up speed and how prolonged the animation is until he stops and starts going again - I'll reserve judgement until I get my hands on it.
But besides that, the game's looks are everything that Sonic fans have wished for. Let's just hope we get Dr. Robotnik and no Dr. Eggman this time around - man, I hate that name.