Continuity mistake: Early in the movie, Mac throws the dead green berets' dog tags to Dutch. As he catches them, Dutch has his hand closed in a fist, and the dog tags are hanging to the left. But in the close-up shot where we can read the name, his fingers are more open, with the tags resting in his palm.
Continuity mistake: In the chopper, as Arnold asks about the backup, you can see Poncho sitting on the other side of Dillon. It's not until later in the scene where Poncho moves from his seat and sits next to Dillon for the remainder of the scene.
Continuity mistake: While the team are hearing the music on the chopper, the pushed buttons on the recorder change - the third one, then the fourth, then none.
Continuity mistake: Before the team finds the crashed chopper Dutch has just a bit of camouflage on his face but after that he has more.
Continuity mistake: At the beginning while Dutch meets with Dillon the cigar in his hands disappears and reappears between shots.
Continuity mistake: When Mac first shoots up the jungle, he runs out of ammo. From the behind shot the barrel of the mini gun isn't spinning. Then, from the front shot when Mac releases it the barrel is spinning. (01:46:25 - 02:46:30)
Continuity mistake: When Mac calls to Dillon about the scorpion you can see that there wasn't one on his back to begin with.
Continuity mistake: The bullet riddled tree that Poncho is hiding behind changes. It goes from severely riddled to not as much damage.
Answer: In the shots where we can see what the Predator sees, sometimes when he is focusing on someone or something, we hear a kind of flash noise as he zooms in on the object. When we see the Predator's eyes flashing/glowing, that is when he is zooming in on what he's looking at.
dan coakley..