Aonuma discusses main gameplay elements in Twilight Princess

While Aonuma didn't say much of anything that we don't already know about Twilight Princess, he did sum up a few things in a little more detail.

Midna (the character on wolf Link's back) is a very important character. Important to story, to puzzles, and all around gameplay.

Twilight Princess has a day/night system. This system will be used to deliver key events in the story during certain parts of the day/night cycle.

Link will be able to talk with animals to solve puzzles and find out story information. Whether you will talk to the animals while in wolf/non wolf is unknown.

Link will be spending a lot of time running around with his lantern. Many of the areas in the game are dark, spooky, and made all that much more scary by searching them in the dark.