Continuity mistake: At the very end of the film. When the 3 helicopters and the seaplane come into land, it is quite a wide shot, with no boats visible. A few minutes later, when the seaplane takes off again, a big white boat is near the coast. Even if the boat was off camera during the landing scene, a few minutes was surely not enough to get that far, and that close to the shore.
Continuity mistake: During the shooting scene by the mansion, the same poor soldier gets killed from different angles, again and again and AGAIN....
Continuity mistake: When Arnold lets go of the landing gear he lands in the water. A few seconds later we see him walking up towards the beach, and we can now see that he is only wet from his waist down. It's not likely that he would have been able to land standing on his feet and not not becoming completely soaked.
Continuity mistake: Rae fires a rocket at the police van, first she fires it back to front then the second time she fires it correctly only this time she is knocked back by the recoil, why wasn't she affected the first time and pushed forward? Also there should be no recoil with a rocket launch.
Audio problem: The scene where Bennet and Matrix are fighting towards the end of the movie, before Matrix kills Bennet they have each others throat in their hands and one of their backs is against the furnace. While they are grunting and groaning, if you listen carefully, you can hear one of them say "switch" just before they change positions.
Continuity mistake: At the end of the movie, Arnie puts on his flak jacket then his make-up, but when he takes off his jacket, he's got camouflage on.
Continuity mistake: When Matrix is infiltrating the base (just before he blows everything up), and just after he has cut a soldier's throat and planted a bomb, he is confronted by two more soldiers walking along with rifles slung. Seeing Matrix, the two frantically start un-slinging their rifles. Matrix throws two knives at them. Next we see the two soldiers falling with knives in their throats... and the one on the right has his rifle fully slung again.