I would suggest reading it all simply because Ueda is a genius, but I've quoted some interesting parts.
Fumito Ueda Talks Trico
The director discusses creature design and gameplay.
First, some naming issues. The game that eventually came to be known as The Last Guardian has been referred to by fans for some time now as "Trico," as it's the third project from the team that gained world attention with ICO on the PS2. You might also start hearing about the game by another name: "Hito Kui no Oowashi Toriko." That's the official Japanese name, as listed in Famitsu. It literally translates to "The Giant Man-Eating Eagle Toriko." More on the word "Toriko" in just a bit.
According to Ueda, having a giant living creature was the first idea to emerge when creating the game. Ueda hoped to make the relationship between the player and Agro, the horse from Shadow of the Colossus, a bit more central to the game design this time.
As you might have guessed, players take control of the little boy from the trailer. The basic game design has the boy being young and thus weak and lacking abilities. The giant eagle makes up for these areas. As a young boy, the main character cannot rely on his strength to get past obstacles. However, perhaps he can overcome some trials by bringing the eagle with him.
While Ueda wouldn't reveal how the boy comes to meet the eagle, he was a bit (just a bit) more forthcoming with details on what you'll do in the game.
Interacting with the eagle appears to be one of the central aspects to the game. You're free to touch the eagle whenever you like. Its reactions will differ depending on where you touch it.
There's a care aspect for the eagle as well. You can feed the eagle and remove spears and arrows that have pierced it. Ueda feels that the development staff will have to take care to strike a balance and make sure the care aspects do not becoming a chore.
Growth and stage puzzles are major elements to the game. There are platforming aspects as well -- you can climb, grab things and crawl.
The flow of the game is a bit of a mystery right now. Asked if your movement through the stages will be seamless, Uedo said that it's seamless as far as there being no load times as you move about. However, there is an order to the locations that you visit.
With Last Guardian, however, one area of the stage design involves how you go about getting the eagle to do stuff for you. You can either order it around, or you can have it cooperate with you. For instance, you could make the eagle move by throwing around something that it likes.
For this third project, Team ICO is making use of some advanced technology. Different from their past titles, they're using real physics. As an example of this, Ueda made note of a scene where the creature eats a barrel. This is not done with motion capture, but with actual physical calculations involving the barrel and the creature's mouth.
Uedo also noted the game's pairing of the AI of ICO and the collision schemes of Shadow of the Colossus. This older technology has all been redone at PS3 levels.
The staff is paying great attention to one particular environmental effect: wind. The wind determines how the eagle's feathers sway. Each feather is processed individually.