And it's damned difficult to get any better gameplay, either. Yes, you'll probably beat it in well under ten hours, but
ICO is one of the most satisfying gameplay experiences you'll ever have. Not once did I feel that I was being sidetracked for an hour or two because the developers were trying to wring a few more minutes out of the game design, and every puzzle in the game seems logical (a few of them only in retrospect, after much gnashing of teeth). This is a world where you don't have to fetch the stupid item and run all the way across a stupid map to give it to some moron; the challenge is in the environment, and in making sure Yorda makes it out with you.
The concept of the game is simple enough. You are Ico, a young boy with horns who is ritually 'sacrificed' (read: buried alive) in a castle because of his freakish nature when he turns 12. A small earthquake occurs, and his sarcophagus breaks free, letting him out. Soon after, he encounters Yorda, an ethereally beautiful young girl inside a cage. After freeing her and fighting off the first group of shadow creatures, he takes it upon himself to get her out as well. And so the quest begins--an attempted escape from the castle, Yorda in tow.
Ico himself moves much like any platformer action hero. He can make long jumps, climb things, shimmy across bars, and the like. Yorda, on the other hand, can't jump very far and can't climb at all. If you leave the 'zone' that she's in for very long at all, she gets attacked by the shadow beasts, and if she ever gets taken by them it's Game Over, so you have to make sure to take her with you wherever you go. This often requires some very careful manipulation of the environment, moving things and pulling switches that manage to create a path for her.
It may sound a little contrived, but in the game itself it never feels like that. Switches usually control winches with dangling chains, instead of some other magic device. And it's fairly obvious that the bad guy--or woman, in this case--is trying to make it as difficult as possible for Ico and Yorda to escape.
There is both a lot more and nothing more to say about the gameplay. It ranges all across the castle, and the game's interconnectedness is downright amazing. You'll revisit just about every area of the castle once or twice, giving you a real sense of location that most games don't come close to managing. The game is relatively short--I beat it in seven hours or so, and most people probably won't take more than ten--but it's some of the most enjoyable hours I've ever spent gaming, and I'm debating whether or not I should run through it one more time just for the hell of it. It's that good.