Although we\'ve had our differences as of late, I think this is a really excellent question.
Much like the of the IGN editors inability to take screenshots and movies that accurately show the greatness of the game, I am also finding the same difficulty putting into words exactly why this game is so grand. Perhaps it\'s the concept behind the game that is really original.
Think about it for a moment. What other games require you to break out of a veritable prison with a helpless being in tow? I honestly can\'t think of any. We all know Zelda requires people to enter castles, defeat the enemy, rescue the princess and then restore freedom to Hyrule or something of that nature, but rarely has a game built upon the concept of escape with being a bodyguard as the chief source of the combat engine.
The chief responsibility of the main character behind most games is to ensure your own survival and in affect, saving many others, but in ICO, your job is to ensure the survival of another with your life being the one that\'s expendable. It\'s not like those cheap escort missions present in Starfighter or Ace Combat, but rather a type of mission bent on mercy where you actually care for the "cargo" in tow.
ICO has touched me enough to make me WANT to save the girl from all harm and has made me deeply concerned with her safety. Concerned enough to the point that to see her in the clutches of the "smoke demons" is almost too difficult of a site to bear and I immediately feel the need to exact revenge against them. Kind of like the "Get away from her you B*TCH!" mentality found between Newt and Ripley in Aliens.
I suppose the idea of protecting a precious cargo from all harm is fairly unique to me especially since I feel the need to assist the plight of the cargo. I know I don\'t feel attached to a precious mineral in the cargo hold of some ship a light year away, nor do I feel the urgency to save Princess Zelda from Ganon because I know that after 6 dungeons of exploration, 50 items required, and enough land traveled by foot to make even Forrest Gump jealous, she\'ll still be there even as I effortlessly search for that last piece of heart or rare item. ICO however, does not have the luxury of time, it has a level of urgency that just makes you feel like you need to work to make sure she\'s ok.
Or maybe I\'m just full of crap, but that is just my opinion.