I finshed the campaign yesterday. It was fun, with a great atmosphere and the storytelling was wonderful, but it could have been longer. 8 missions (and a lot of "tutorial feeling") aren't enaugh... I'm playing the six extra missions now and try to get some achievements there. I'm glad I'm still discovering a lot of new gameplay element nows, even after completung the campaign. They added a lot of nice new ideas to this game, which keep you exploring the world.