Corrected entry: The helicopter wreck in the trees is only a junk fuselage. If you study it there is nothing in it at all; even the instrument panel is nothing but mounting holes. This was obviously done to save film costs over using a real unit. The script adds the line "they stripped the s**t out of it" to cover the discrepancy.
Corrected entry: Arnie takes a 40mm M203 grenade, removes the projectile and ties it to an arrow to fire at the predator. This would not work. The M203 is a rifled launcher (the barrel has grooves to make the grenade spin for greater stability). In order to prevent accidental detonation, the shell has an internal safety pin that relies on the centrifugal force generated by the spin to deactivate it.
Corrected entry: Towards the end of the movie, when Anna is now trusted by Dutch and the team, Anna tries to help by wanting to carry a weapon. Dutch warns her not to carry a weapon because he's figured out that the Predator does not think it's sporting to kill an unarmed person and said this why the Predator did not kill her before. Since Dutch believes this, he should have ordered his men to drop all their weapons and then they all could simply walk out of the jungle safely.
Corrected entry: In the scene where the soldiers are attacking the guerilla camp, Jesse Ventura fires his minigun at a sniper's nest, which subsequently explodes in a massive ball of flames. I point this out because the minigun he uses fires full metal jacket rifle rounds, and they are not explosive, nor would they cause a structure comprised of wood to suddenly explode in the way it does.
Corrected entry: In the scene where Mac and Dillon attempt to kill the predator you see the rear view of Mac's head being blown clean off his shoulders, yet when Dillon discovers his lifeless corpse a few moments later his head is intact and there is merely a trickle of blood running from his forehead.
Corrected entry: Towards the end of the movie Arnold swims out of a pond onto a log. Before he can fully emerge the Predator stabs his retractable knives into the log, conveniently fitting around the width of Arnold's neck. The next angle you can see this better when the Predator is directly over Arnold, the knives have a huge gap between them. The knife prop was obviously made just for this scene, because later on the Predator uses the knives again and they are at the normal width.
Corrected entry: When Dutch and his team find the crashed helicopter they use a grappling hook to climb up, on the interior shots you can see the grappling hook attached to the bottom of the helicopters doorway (it almost skewers Poncho in the stomach as he climbs in) but in the exterior shots you can see that the rope is attached to the helicopter well above the doorway.
Corrected entry: It's impossible to shoot a minigun while standing on the ground because: that was a six barreled rotary American minigun, that weights 110-120kg unloaded. It shoots 4000-10000 rounds per minute. For about that 20 seconds it uses 2000-3000 bullets (those weigh about 50kg) and it needs a 4KWt electrical drive (provided in this case by a cable hidden from view - hard to come by in the jungle). Altogether, it's about 200kg. Even the strongest man won't be able to carry this load, much less fire it with any chance to hit, due to extremely powerful recoil and possible injuries from the fast and violently ejecting empty cases. Jesse Ventura had to wear a bulletproof jacket even when firing blanks for that reason.
Corrected entry: In the scene when they find Harper's body skinned in the trees, they throw Dutch the dog tags. They make a large noise when he catches them - But when he looks down, the dog tags are wearing silencers (plastic around the edges). A good soldier would be wearing silencers to keep their approach a secret - the adviser knew that. The foley guy didn't know it and must have added the sounds later. (00:16:35)
Corrected entry: When Dutch is battling the Predator one on one and he is in the tree, after he shoots the explosive tipped arrow the Predator starts shooting off plasma bursts very rapidly. After a minute or so of these bursts causing sparks to shower down on him, Dutch is either ejected or falls from the tree and when he lands on the ground if you watch closely you can see the ground bounce where he lands.Tobin OReilly
Corrected entry: Arnie covers himself in cool mud because the Predator sees heat. But, they are in the middle of hot jungle. The jungle's temperature would surely be hotter than 98.6, or at least close to that. That means that the Predator would see all the air around him as red, not just the humans.
Corrected entry: Watch when Mac shaves himself. He digs the razor into his face and the razor breaks. Look at the blood on his face. After the razor breaks the amount of blood decreases. That is because the prop razor contained the blood and was released when pressed down.
Corrected entry: When Arnold is rushing down the river and over the waterfall its daylight and you can see the blue sky as he swims out of the water. But just after he gets out of the water and sits down under the tree roots, with the Predator after him, it suddenly gets very dark then it's night time in a matter of seconds.
Corrected entry: When Arnold is running away from the Predator he slides down a hill and falls off a cliff into the river below. In the sequence following we see him get washed down the river over waterfalls and such. When he climbs out of the river onto the mud, we see the Predator's invisible body dive into the water, making a small splash. There are two mistakes in this scene. 1. When Arnold crawls up the bank into the mud there are no cliffs around from where the Predator could have dived from, there are only trees. And if the Predator did dive from the trees, he would have easily seen Arnold getting out of the river. 2. Juding by the splash made, the Predator did a head first dive into the water. But from any height this would have broken his neck because the river would have been too shallow.
Corrected entry: In the scene where the team discover the helicopter hanging from the trees, one of the soldiers climbs up into the helicopter. In one shot you see the soldier climb into the helicopter but in the next shot the soldier is still just looking inside.