I worked on a few small props for killzone2 below- They were fast and fun.
I got a chance to play Killzone2 a couple days ago, and I found that it's one of the most realistic shooters I've seen so far. They spent alot of time on lighting and set creation to make their levels enjoyable for the player. The killzone art style is very different. If you've played through you'll notice that most of the textures are low contrast and have no primary colors.