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)
Visible crew/equipment: Dillon again, after having his (visible) arm shot off the Predator moves in and picks him up off the floor, at the bottom of the screen you can see the plank that is used to elevate him. (Only visible on the full-frame video).
Visible crew/equipment: When Dutch is swimming to shore in the first mud scene, at the top of the screen, there are wires or cables visible, running roughly horizontally in an elevated position, with some kind of device affixed. (01:18:24)
Visible crew/equipment: During the final battle, shortly after Dutch runs by a plant that moves and catches the Predator's eye, watch as the Predator takes a few strides from rock to rock. When he jumps down off the last rock you can see a cable above his head helping him make his jump. This same cable can also be seen from a different shot about ten seconds later when Dutch runs into the Predator. (01:29:45)
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.
Visible crew/equipment: When Arnie says 'oh s***' and falls off the cliff, watch as the camera goes over the edge. If you look on the mountain, you can see a shadow of a black ball with a cable attached: this is the camera filming the shot which has been thrown off the cliff.
Continuity mistake: After Dutch has defeated the Predator, right before the 'What the hell are you?' exchange, the Predator spits some neon blood onto its face which immediately disappears.
Continuity mistake: When Dutch (Arnold) has been shot in the arm by the Predator, the wound changes between shots.
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)
Continuity mistake: The first time Anna tries to escape she is stopped by Poncho. He confronts Dillon and tells him to put her on a leash, then raises his gun. Cut to Anna and he raises the gun again. (00:37:30)
Continuity mistake: When Arnold had his face in the mud after swimming to shore to escape the predator, He looks back at the predator and his face is 1/2 covered with mud. The scene's after this his whole face and is covered.
Audio problem: After Dutch has fired the rocket at the Predator standing on the log, the Predator shoots several times. Then you can hear it shoot one more time, but you can't see any blast coming from it. (01:24:35)
Visible crew/equipment: Watch when Arnie is sliding down the cliff: it shows a shot from his eyes looking down at his feet, and you can see the wooden platform he's sliding down.
Continuity mistake: In the shot where Mac finally runs out of minigun ammo, the barrels stop turning. However, the whirring continues and the barrels are still turning in later shots. He didn't let go and pull the trigger again because the whirring was continuous. (00:48:25)
Visible crew/equipment: When Dutch is going to check the area of the trap and to lure on Predator, there are visible some boxes at the top right corner of the shot. Probably set equipment. (01:06:00)
Audio problem: When Anna hits Poncho and takes off running, Arnie "whistles" at Hawkins with his mouth closed and the camera is looking directly at him when it happens. (00:41:05)
Suggested correction: The whistle is a tongue whistle. The tongue is curved via the teeth and the lips need to be almost closed to make the air rush out in that manner. It's sharper than a regular whistle due to this.
Continuity mistake: In the first 20 minutes the camouflage on Dutch's face keeps changing between shots - black stripes on his forehead keep changing and then green stripes are added later in continuing scenes.
