By saying "classic" or "remastered," you'll be able to swap between the two versions of the game.
We should know the rest of the Kinect features soon enough, sometime next month.
"We don't want to oversell it," said O'Connor. "It's not something that radically changes the gameplay; it's just another additive bonus on top of the other stuff we've added. We think of it like the 3D: something that makes the experience better, but doesn't change it."