I don't think I've ever taken longer than about four hours to beat it, even on my first try, but it really doesn't matter because it's an experience that's as close to 100% gameplay as you're likely to find these days. You never have to pause the game to bring up a menu to change equipment or boost stats or heal, and besides the opening and ending, no cut-scene lasts for more than a minute--and they're few, anyway.

You really can't play this game looking at it out of the corner of one eye. Puzzles are complex and thought-provoking without being too contrived; every obstacle set in your path and every tool you find to surmount them seem like natural parts of the castle environment. The most important part of playing the game, however, is looking after the girl, Yorda. As frail as she is, Yorda adds another layer of complexity to the puzzles: instead of "get from Point A to Point B," the objective becomes "get from Point A to Point B and then find an alternate way back to the Point A so that Yorda can get to Point B, too, but don't leave her alone at Point A too long, or the shadow minions will emerge and attack her." Protecting Yorda also makes combat constantly frantic and involving, since her tough-to-kill assailants tend to swarm all around her like a pack of wolves, making it necessary to be alert at all times.

I love ICO so much.