The problem with arcade-style racing games, according to Fulton, is that the appeal of racing different vehicles is lost due to the fact that all cars have to handle roughly the same in order to preserve an "arcade" feel. By using Forza's existing physics engine, Playground Games hopes to circumnavigate this problem and preserve the series' pedigree for for automotive accuracy.
That being said, the only car featured in the demonstration I saw was the 2013 SRT Viper, and as it was a hands-off demonstration, I was unable to compare its handling with my experience driving similar cars in previous Forza games. What I can say, is that the Viper did more than its fair share of drifting around Colorado's mountain roads, and that it racked up wicked popularity points doing so. See, in Forza Horizon, you're not just driving around for the hell of it. You're driving to get famous. The game is centered around a fictional music/automotive event, the eponymous Horizon Festival, and all the sweet jumps and crazy drifts you do around the world work toward building your reputation as a radical driver with the festival's attendees. While it's possible to earn points while driving aimlessly around the countryside, the majority of the points you'll earn will likely come from participating in one of the many driving events scattered throughout the world.
Many other drivers have also come to the Horizon Festival to make a name for themselves, and as such there are multitudes of computer-controlled drivers strewn about Colorado just itching to test their mettle (and metal) against yours. The game features both circuit and point-to-point events, which take place on 65 different surface types that cars realistically respond to (Fulton said that the cars' physics are adjusted 100 times a second). Should you ever get lost while attempting to locate one of these races out in Horizon's open world, you can always use the game's GPS system, provided you own the requisite Kinect.
Forza Horizon will be the first game in the series to offer off-road races, which I assume will take the form of either rally or rallycross, though no actual events were show during the demonstration I attended. Every event type that does exist in the world, however, will also be available in the game's multiplayer modes.
Forza Horizon's licensed soundtrack is also presently indeterminate, though I did learn that the game will feature three genre-themed radio stations (Electro, Rock and Indie), each curated by British DJ Rob Da Bank. For what it's worth, I distinctly heard the familiar wubs of Skrillex underneath the throaty roar of the SRT Viper.
Forza Horizon will drift onto 360s come October 23, 2012.