Underrated.
The gameplay is a delicate balance of fats-and-furious firefights, and simple puzzles and searching for items. Works quite well. The rag doll physics are awesome. Not too many games let you throw a grenade in room, shut the door, and see the enemy body fly out of the window, only to go inside the room to find several legs or arms, or even a head. Very bloody, and gory, which helps with the dark setting.
But the thing that keeps bringing me back is the splitscreen mode. If you have a buddy or two to play with, it's brutal fun. But it's also killer fun to do it single player style, with 3 bots, and the ability to create your own weapons arsenal is pretty cool. The Sterlings Winter level with all shotguns is great fun.
In all, go and try to find this game, you won't regret it.