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)
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: 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.
Continuity mistake: During the montage scene of the remaining men setting the net trap for the Predator, all of the men are each doing individual jobs. Dillon does not take part initially, until Arnold says 'Instead of complaining, maybe you should help.' However, long before Arnold tells Dillon to help, Dillon can actually be seen helping out already. Watch closely...when Mac throws a rope across to Billy, Dillon is standing behind Mac, with his shirt off, fastening a rope to a tree, as if he was helping the whole time already. A similar shot occurs after Arnold's comment, but the first one is definitely before. (01:02:05)
Continuity mistake: When Dutch is running from the Predator after he sets the grenade off in the tunnel sequence, he avoids the Predator's gun blast by leaping and swinging on the branch of a dead tree. As Dutch's flying through the air, you can clearly see that it is a real branch. But as the screen switches to an explosion and back to Dutch, the branch is now some prop 2x4 and collapses as Dutch now plunges into the pond below. (01:33:20)