I agree whole heartedly with NGai on this one. From almost the first moment I ever saw footage of KZ2 I disliked it. I was impressed by the graphical prowess and the pretty particle effects, but the art style was so lacklustre and dull that I found it impossible to get excited.
After buying the game, I only played it for 3 or 4 days before taking out of the PS3 and never touching it again, and IMO it stands as one of the most ridiculously over-rated and poorly designed games of this generation alongside Prince of Persia.

Anyway, the point you all seem to be missing is that the art style didn't need to reflect the storyline of KZ2, and this is because the art style and the plotline would have been develped hand in hand. Had the designers wanted to set the game in more interesting and attractive environments, they could have simply changed the plot to match their vision. Let's face it, the storyline for KZ2 is one of the weakest ever seen in a AAA title so it's not like they would have been sacrificing the game's integrity much to throw in a forest or a mountain. The only reason Vekta is war-torn and ugly is because the writers MADE it that way, the reason it has no culture is because the creators didn't bother to make any! This game is fiction, remember, straight out of the imagination of people who apparently think only in the colour grey.

Halo didn't look so lush and beautiful because the plot demanded trees and beaches: they simply chose at an early stage to make a beautiful game. And say what you will about GoW's 'Destroyed Beauty' concept, but at least they tried something different.
Killzone subscribes to the exact same Space Marine cliches that have been around since Warhammer 40K and beyond (ESPECIALLY the character models, which are incredibly forgettable...oh, and the Helghast are direct ripoffs from Jin Roh), and I can only assume that the visual concept for the game was 'let's make this look incredibly dull and then cover it all up with shiny particles, yay!'
I'm glad some people found what they wanted in this game, but I honestly don't understand how. Walking through my local run-down town centre gives me all the grey, gritty realism I can stand, and I do not expect the same from videogames.

Good article!