Do yourself a favor and play this game if you have a chance, it's epic.
The primary idea of the game is that you're this little kid named Ico and have to guide another character though the castle while fighting the shade enemies. The story is not too fresh for me anymore but everything works just perfectly for this game. The sense of scale was mind-blowing to me. The background and everything involved is just epic.
Do yourself a favor and play this game if you have a chance, one of the best visuals for the PS2 for sure.