I enjoyed the single player a lot, got sucked in by the atmosphere and music.
The storyline was superb, just too subtle for some peoples craniums .......

Well actually the story is a bit weak because it is simply scene setting the first part of a trilogy - a soldier is ordered to retrieve certain objects against impossible odds and finds that his father has more to do with it than previously realised.....
As a soldier you rarely get told the intricate details of why you are doing things.
I've played a little bit of this co-op and I'd love to play the whole game on co-op, it is a very pretty, very atmospheric FPS with great graphics and music and I personally thought pretty good game play with the diving into cover, the beserkers, boomers and so on.
I've yet to venture online and get my backside toasted by experienced players, might save that shaming experience for later.