Guessed by @Darashiva
Probably the first thing that comes to mind when I hear the word "masterpiece".
Shadow of the Colossus is very much that, because more than its qualities as a videogame, more than its beautiful visuals, its awe-inspiring music, more than the gripping tale of a young kid going to insane lengths to save someone he cares about on a misguided journey, more than any of its individual parts, this is a work of art. It feels like a generation-defining monumental piece, the kind that should be put in a museum, but instead it's on our TV screens to be experienced with a controller in our hands. Because having that controller in hands is how this work of art works. By having someone going through Wander's journey with him, maybe feeling awestruck by the incredible beasts he's faced with and taking them down with him, maybe even taking a sense of pride in the feat of slaying such creatures, with or without realizing how this is nothing more than a quest for revenge, a tale of misguided grief leading someone to cause far more harm than was initially done.
Ahem, sorry if that was kinda spoiler-y.
Videogames are always evolving, the industry is always trying to find the next breakthrough, the next achievement, the next standard of quality. Shadow of the Colossus is beside all that. It will always stand on its own as a timeless work of art.