A gameplay video for the Sonic & Sega All-Stars Racing circuit Seaside Hill has been released on GameTrailers. We have previously seen a video of the Billy Hatcher circuit, but this is one of the first of Seaside Hill, which featured in the original announcement screenshots.
The game refers to the track as "Forgotten Falls", but the game's announcer clearly says "it's race time from the sunny home of racing, Seaside Hill!". The announcer can be heard throughout the race, commentating on the events à la Sonic Riders. The track features classic Sonic enemies such as Crabmeat and Choppers from Green Hill Zone, and placeholder (I hope) Crush 40 music.
The developer in the video says that the final game will have "over 20" power-ups and "over 20" characters. He says we will be "pleasantly surprised" with the final character line-up, which goes back to some of Sega's classic franchises. There will also be "over 20" environments with a lot of variety.
All of the unique vehicles the characters drive have different statistics, for example flying characters (Tails and Eggman) will not be affected by grass unlike the characters closer to the ground. Each character has their own taunts and moves, much like Power Drift, with some people spotting Sonic apparently giving "the finger" or doing a Michael Jackson grab (!).
Boosts can be triggered by the shoe power-up, speed pads and doing tricks in the air. "Star Moves" allow the characters to speed up - we have previously seen Sonic turning into his Super form, and AiAi speeding in his Monkey Ball in this particular video.
The developer says some surprises will be announced over the coming months, with no hints as to what those could be. Forklifts? Maybe.