Play with dogs, throw things in 3D.
I played with two of the three dogs available, beagle and labrador. The environment and dogs looked the same as the ones on the current Nintendogs games. The menu was different, with a list of supplies to choose from. There were a few toys including frisbee and boomerang, and then several outfit options such as a Mario hat and sunglasses. There were no supplies for feeding or cleaning. This limits interacting with the Nintendogs to fetch and dress up, and calling the dog closer for petting.
I didn't find that the 3D made it any more interesting. There wasn't much to explore in the demo, and we will have to wait and see what happens when the more interesting activities and cats are added to the mix.