(at around 13 mins) The reporter and a few marines are under sniper fire while walking. We hear the sound of the gunshot, and the bullet strikes the ground near the marine's feet about a second later. That is not possible, since all rifles fire supersonic bullets; one would normally first see the bullet hitting, and then after a short interval (increasing in duration with the distance) hear the sound of the gunshot.
Several times throughout series characters give times as (for example) "2300 hours." Like personnel in the Navy, Marines would only say "2300" since it is understood that the number relates to time and "hours" would be redundant. Other armed services like the Army and Air Force would use "hours" after the time.