Revealing mistake: As the Predator tends to his wounded leg, one of his claws can be seen bending as if made of rubber.
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].
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)
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)
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.
Revealing mistake: When Bill Duke picks the scorpion off Carl Weathers' shoulder with a knife, you can blatantly see some gum or similar that's been used to stick the scorpion onto the tip of the knife. Even if it's meant to be Bill Duke's gum, it's not on the tip of the knife before he stabs it.
Suggested correction: It isn't gum, it's literally the scorpion's guts.
There are no guts in the scorpion's body, so it's obviously some material to stick scorpion to the tip of the knife, and it's blatantly visible in the close shot.
It's the abdominal fluid. It probably is gum in real life but if you kill an insect you will find it has a gum-like fluid in its abdomen.
Revealing mistake: After they catch the Predator in the net and it breaks free, the laser blast breaks a big part of a tree and it heads toward a soldier, hitting him head on. If you watch closely when they show an above shot of the tree hitting the guy, you can see an air pressured pad pushing the tree on the ground into him. (01:06:40)
Revealing mistake: Watch when the Predator reaches over to activate his self-destruct mechanism. The wristblades clip right through the glowing special effect on his blood. (01:40:05)
Revealing mistake: When Arnold is heading into the trees after building his bow and arrows you can see a silver eye bolt on the top of the bow where the string would attach.
Revealing mistake: When Billy cuts his chest before facing the predator, it's obvious that there's a blood tube on the back of the blade. The blood gets "spread" onto his chest like butter on toast whereas in reality a cut forms and then blood beads out and flows moments later.
Revealing mistake: In the scene when Anna first tries to escape and is stopped by Poncho, Dillon picks her up. If you look closely one of Anna's hands has slipped out of her cuffs yet she is still holding her hands together as if she's bound. (00:37:35)
Revealing mistake: When Dillon and Anna are arguing in the terrorists hideout near the burnt out helicopter, the corpse on the ground behind them moves his foot.
Revealing mistake: While the Predator is healing himself with his surgical material, the marks of the brands are visible.
Revealing mistake: While Dutch is struggling with the Predator in the jungle, in several shots the stuntman is visible.
Revealing mistake: Blaine is dead in the body bag, but when Mac puts the flask on his neck, you see his pulse.
