Its a good game, but (and its a GIGANTIC BUT) even the campaign mode is Ironman only. Meaning one tiny mistake and you get to play the whole mission from the beginning again and for spending extra 2 hrs on that campaign you get a very satisfying 10% rewards deduction at the end of it (oh and 10% more for subsequent fu*kups)
Great for hardcore gamers with a lot of time and passion to devote to this one game to grind and learn to become almost a zombie themselves.
For casual players, not so much. Any kind of distraction and you're stuck playing the same map, same specs, same build for the next 2 hrs hoping nothing distracts you again.