The much maligned Never Trust a Trailer aspect of the marketing for this movie is actually fitting. It would in fact be a major spoiler to reveal the (now well known) fact that they never do any fighting. The beginning of this movie is similar to the beginning of any number of other war movies, and it initially looks like it is just the first part of a buildup of tension to a release in combat. It just happens in this movie that that never comes. That every tense moment that looks like it will lead to combat ends in disappointment is supposed to be as much a surprise to the audience as it is to the characters. It is ultimately a film about a massive buildup of tension for an end that never comes. Making the audience think it's a traditional war movie going in makes us feel the same sense of disappointment that the characters feel at never getting to fight. It makes the point of the film that much more poignant because we have now shared in it.