The action is plentiful, the gore is all over the place and the suspense is well executed. I did end up getting tired of the constant boring gun battles though as if you have seen one, you've seen them all. The stand out parts of the game are the scary bits which kept me going.
Level design is fairly linear and boxey but keeps the action well contained and moving. The guns are much of a muchness and follow the generic FPS weapon sheet almost to the letter (the penetrator being the only standout weapon for me).
The storyline is rather vague and not particularly well written but does serve to provide a basis for things. Player characters are also nicely done if not a little easily distracted and minced.
Quite and enjoyable game.