Imagine enlisting in the Marines, going through one hell after another, to finally get deployed in Operation Desert Shield. Once deployed, you fight boredom for months, until finally Operation Desert Storm begins. Imagine you get shot at with no opportunity to shoot back. Imagine going through hell again, until finally, after a long period of difficulty, you are finally looking at the enemy through the sight of a gun. All the misery you have gone through comes down to what you do at that one critical moment. That's what Jarhead is about. What happens at that moment I can't reveal, but it is not what I expected.
The movie captures the difficulty, boredom and insanity of being at war. It wouldn't make a good recruitment film, because none of this looks pleasant.