When Swoff walks into a command and communications tent, a few of the Marines are using personal computers with flat panel consumer brand LCD monitors. These would not have been available in 1991 during the first Gulf War.
The chartered planes aboard which the Marines arrive in the Middle East are 747-400s, which were not yet in service in 1990, and which were never operated by TWA before it was acquired by American Airlines. (TWA operated 747-100s and 747-200s.)
When the A-10 Warthogs attack marines accidentally in the desert, neither the sound of the GAU-8 Avenger nor the bullet hits are even close to real. The A-10 main (and only) gun shoots 30 mm depleted uranium and high-explosive bullets at 4200 rounds per minute. These bullets can penetrate 69 mm of armor and they'll rise significant amount of dirt in the air. The gun sound is more like giant hammer drill against a rock.
Whenever snipers are shooting at their targets their spotter does a countdown by saying "Fire! Fire! Fire!". The sniper then fires on the third "Fire!" to ensure a well-timed kill. However, in the movie the snipers fire whenever they want after the spotter says the third "Fire!".
Swofford's rifle points towards Troy's face while they're low-crawling towards the Iraqi compound. The U.S. Marine Corps considers this a safety violation. First weapons safety rule: never point a weapon at anything you do not intend to shoot.
In the Interview section in the Bonus Features, Jake's character confuses Iraqis with Saudis when he is asked how he feels about the Iraqis. He also confuses Kuwaitis with Iraqis when he is asked how he feels about Kuwaitis. In the commentary it was noted that they allowed the actors to ad-lib a lot of the interview material.
Troy gives the range from their position to the Iraqi officers in the control tower as "900 yards." His rangefinder and Swofford's rifle scope would both be configured in meters. The U.S. military uses the Metric system to ensure commonality with their NATO allies.
When they first arrive in Saudi they are in a tent when SSGT yells gas, and Swoffard tries to get his NBC Suit on first. All military are trained to put on their protective mask up first before before getting the rest of their MOPP gear on.
One of the marines mentions "getting to level 9" on Metroid. Another responds that you just have to start over again after you win. Metroid, however, does not have levels and when the game is completed, it does not start over.
At roughly 29 minutes 38 seconds into the movie the scout/sniper Marines are urinating, or dehydrating as Swofford words it. All of them have their rifles on them except for one: third Marine from the end of the line on the left side of the camera angle who swings his hips left and right.
When Fergus is cooking sausages on the gas stove the fire spreads to the surrounding area in the back of the truck. As we see Fergus try to put it out the fire the stove clearly falls over. The scene then cuts away and then returns and the stove is once again upright.
In the final desert scene at the night-time party when Swoff and Troy arrive and begin shooting into the air, the camera cuts to a other men at the party also firing into the air. Swoff begins by firing his sniper rifle but when the camera goes back to him his weapon has switched to a light belt-fed machine gun.
When Swoff is getting his first firing training to be a Scout Sniper, his first shot is fired and he scores a hit on the upper right side of the target in the head. When he re-chambers to prepare for his next shot and we see through his cross-hairs, his last shot appears to have been a bullseye in left center of the head.
When the Marines arrive at the hot zone SSgt Sykes walks out from behind the truck carrying the Marines. In the shot Sykes is wearing the goggles fitted on his helmet. In the shot following that, the goggles are off his face and mounted on his helmet.
When Swoff first learns that Troy was turned down for reenlistment, the platoon is digging sleeping holes in the sand. Later, when Troy gets his brand, they're all in a large tent. Afterwards they're back in the open and there's no sign of a tent in the immediate vicinity.
When Swoff's squad arrives at the "Highway of Death" a road sign in the background reads "Abdali 150 KM, Kazimah 80 KM, Mutlaa 10 KM". There is nowhere in Kuwait where all three of these distances would be accurate: Al-Mutla and Kazimah are only about 10 to 15 kilometres from each other, and Al-Abdali commune is only roughly 70 to 80 kilometres from those two districts and roughly 90 to 100 kilometres from Kuwait City. Most of the carnage on the "Highway of Death" took place along Highway 80, in the area around Mutla which would have put Abdali only 70 to 75 kilometres and Kazimah only 10 to 15 kilometres away.
In the scorpion fight scene, there is a Emperor Scorpion (P. imperator) and Desert Hairy Scorpion (H. arizonensis). The former is native to Congolese Africa, the latter to Arizona and surrounding states. Neither has any place anywhere in the Middle East.
When the new Marines first meet SSGT Sykes, the water tower in the background has a USAF Tactical Air Command or USAF Air Combat Command emblem on it, which new Marines would never see at Camp Pendleton. This scene was filmed at George AFB in Victorville CA.
The Marine officers look as though they're wearing standard, shiny officer badges. Marine officers do not wear standard badges during deployments because it would give away their rank to the enemy. They wear non-standard badges to maintain a low profile.
When the Marines are celebrating the end of the war firing their weapons, Troy is shown pulling down on the trigger of his M16A2 rifle. This should produce a three round burst. However, it is incorrectly firing fully automatically. The only rifles of the M16A2 design capable of automatic fire are the modified version designated M16A3, which was only used by select units and was not adopted until five years after this scene was set, in 1996.
When SSgt. Sykes takes the platoon on a run after failing the gas drill, the platoon is in full MOPP gear, but SSgt. Sykes is not. This is a big no-no in the USMC because leaders are expected to lead from the front, so he should have been in full MOPP gear as well.
When they first arrive in Saudi they are in a tent when SSGT yells gas, Swoffard tries to get his NBC Suit on first, All military are trained to put on their protective mask up first before before getting the rest of their MOPP gear on. This is part of Basic Training and should have been 2nd nature to someone who has trained all the way up to scout sniper school.
In some night scenes, for instance during the party after the Marines return to the base, the orange lights standing in for burning oil wells are visible. These lights were supposed to be digitally replaced with fire in post-production.
When the sausages caught the truck load of para-flares on fire, they would not have shot up in the sky as they are all laying on their side in the crate. They would have been all over the compound. They would have been in a secure area to begin with and not so close to living areas.