Make no mistake, it's clearly a looker. But so what. At some point the visual novelty wears off and you're left with a game that either worked, or didn't, or fell somewhere in limbo-land between.
Which makes it fortunate that Killzone 2 not only works, but in most cases excels. Even its mediocre campaign improves if you treat it as the developer's intended – a series of pitched battles designed to showcase an AI that's at worst entirely competent, and at best, remarkable.