Revealing mistake: As the Predator tends to his wounded leg, one of his claws can be seen bending as if made of rubber.
Continuity mistake: After Mac has stabbed the scorpion that was on Dillon's back, he puts on a box and crushes it with his boot. You see a clear picture before he crushes it and then after he lifts his boot away. It is facing a completely different direction than before he stands on it. (00:32:25)
Revealing mistake: Mac and Dillon go after the Predator. The Predator is sitting in a tree, and Mac points him out to Dillon. They both agree that they see it and take position. Mac crawls underneath the alien and is killed by his laser. The Predator then sees Dillon and lasers his arm off. Dillon's arm falls to the ground with the gun firing. Quickly Dillon turns and reaches for the machine gun around his neck. When he turns you clearly see his bloody right stump and his right arm sticking out the bottom of his jacket. [Note: As far as I can work out, this has been cunningly edited out of the UK DVD version].
Factual error: The heat from Dutch's body would warm the mud up in a matter of seconds (tested by the Mythbusters). It doesn't even cover all of his skin or his eyes. And the Predator isn't filtering his input for only large heat sources. His normal vision tracks in on a rat hiding just above Dutch.
Factual error: The predator enters the compound and picks up the scorpion. The silhouette of the scorpion changes from bright to dark, showing a drop in temperature. But scorpions are cold blooded animals who have an ambient temperature. The predator should never have seen it at all.
Continuity mistake: In the scene at the end when Arnie crawls into the booby trapped gully you can see the Predator behind him with the knives on his right arm already extended. The camera then switches to a shot of the Predator extending the knives to finish Arnie off.
Revealing mistake: In the scene where Dutch is being chased by the Predator, near the end, he jumps into a waterfall. When you see him take a high-dive, it is archive footage of a different person, filmed on a different camera. When it cuts straight back to Arnie, you can see that it was a completely different place as well. When you know to look for it, this is really obvious. (01:17:05)
Continuity mistake: Billy carries an M-16 with an attachment under it when he leaves the burned village. When it shows him again the M-16 has no attachment. Right after that it shows him again and it's back. (00:35:15)
Factual error: Ventura carried the M134 Minigun and an ammo pack which holds 500 rounds. At its firing rate, that ammo would be spent within a matter of seconds, not minutes as was seen in the movie. (00:47:45)
Revealing mistake: When the Predator self-destructs and the people in the chopper look out at the blast, the "painting" of the explosion is still and does not move or change like a normal explosion would. (01:41:05)
Continuity mistake: Near the end of the film, Arnold is lying in wait for the Predator after he lights the bonfire. It is pitch-black, except for the moonlight and the fire. But in the shot when the Predator jumps down through the trees, the skyline is brighter - almost early evening in brightness.
Continuity mistake: On the attack on the village, Dutch fires a 40mm grenade at a grass hut and there is a soldier that slowly flips over from the blast. Seconds later, Poncho fires another 40mm grenade round, and that same soldier flips over again. (00:24:40)
Visible crew/equipment: When the predator has been hit by Arnie, the camera and cable is reflected on his face. This also happens when Arnie is calling for Billy - you can see it reflected on his arm.
Continuity mistake: When the Predator blasts free of the net and his laser blows off a tree limb; in the first shot you can see the limb is hollow as it is shot off [and I for one have never heard of a hollow tree, but even if they do exist...] as the free limb swings down toward Poncho, you can see that it is no longer hollow, but completely solid. (01:06:40)
Continuity mistake: As Dutch climbs out of the water he crawls through mud. He looks back at the pursuing Predator and crawls backward through the mud. Even with all this crawling there is no way that he would have been covered head to toe in mud. If you look closely every little nook and cranny is full of mud, he would have had to dunk his entire body in a mud pit to accomplish this. (01:19:25)
Continuity mistake: In the scene where the female prisoner falls to the ground and pretends to be hurt, then throws leaves in the soldier's face and tries to escape. She is stopped by another soldier, standing in her path with a gun in her face. The sequence with the gun pointed at her head is filmed in two shots. One looking up at the soldier holding the gun, the other with the gun hovering in her face. Every time it changes between these two camera angles, we find the soldier's hands in two completely different positions on the gun he is holding.
Factual error: In the scene where Dutch is making his improvised explosive arrows we get a close up of him dismantling a 40 mm High explosive grenade and dumping the propellant out onto a large leaf. Way to much powder came out. An actual 40 mm has only about an amount equal to a sewing thimble full.
Suggested correction: It's not clear how much powder came out because it's too dark to see. It could be assumed that it was a lot but it could equally have been not much that took some time, and turning of the shell, to come out. That said, a standard low-velocity, launcher-fired 40 mm grenades generally have explosive loads of 30-50 grams.
Revealing mistake: In several scenes, you can see the BFAs (blank firing adapter) in the team's M16s, proving they've been rigged to fire blanks.
Continuity mistake: In the scene where Anna tries to escape for the first time, and is stopped by a gun to her head, her hat is hanging down over her right shoulder. In the next shot, as Dillon comes to picker her up, her hat is now on her left shoulder. (00:37:20)
Continuity mistake: During the big firefight after Blaine was killed, Dutch moves his hand forward to eject the magazine from his weapon. An instant later, the side view shows his hand on the handgrip and the magazine being ejected - way too quick to get his hand back on the grip.
