If you've been following Fable 2's development at all, you'll know that at the Game Developers Conference last year, it was revealed that one of the main elements of Fable 2's gameplay is a dog. Peter Molyneux (the mastermind behind games like Populous, Dungeon Keeper, and Black & White) said that he wanted to add a canine companion so that you would have a stronger emotional tie to the game in so much that the dog's well-being is of primary concern.
Molyneux also stressed the ease of combat. Each type of weapon in your arsenal (which includes guns, swords, and magic) is mapped to a specific face button. By tapping these buttons, your character will execute a weak version of that particular attack, but by holding it down, you can perform stronger and more dramatic moves.