the story will start with some history, a prologue. this prologue is the first mission the only thing you have to do in it is watch. the second mission is the game itself and happens a week after the first mission.
I did only set one save point in the mission you really have to save it on that point. But there are more difficult parts so save it now and then.
my campain isn't amazing action but it is worth the play.
sorry for the bad spelling of English words I'm Dutch and my English is not so good.