Continuity mistake: We see two thugs waiting for Matrix and the other guy at the airport. When we see a close up of the two thugs, there is no one in front of them. But, as the shot changes to a wider angle, people have appeared that should be visible in the previous shot. (01:06:10)
Continuity mistake: When Matrix arrives to the beach in a rubber boat he has black swim pants on. When he jumps out, they are grey (far shot). When the camera switches back to close up, the pants are black again. (01:07:00)
Continuity mistake: Matrix's camouflage make-up changes style between shots (watch the thick line to the right side of the nose), furthermore, sometimes it's brilliant and shiny, others mat and dry, with no continuity at all. (01:07:25)
Continuity mistake: After Matrix lands on the island and kits himself up, the camera zooms out to show him fully geared up; pay attention to the binoculars hanging from his neck - they are different to the ones he uses a minute or two later. (01:07:35)
Continuity mistake: Halfway through the movie, Matrix is checking out the house where they keep his daughter. We then see a shot that shows what he is seeing through his binoculars, as he looks from the left to the right. Strangely, the landscape seems to move in the same direction as he is moving the binoculars, whereas normally the landscape would be moving in the opposite direction. (01:08:15)
Continuity mistake: When Matrix fires the multi-bazooka at the jeep, just before it explodes, a bunch of boxes covered with bushes suddenly appears right in front, most likely to hide all the stuff to allow for the explossions and chaos that follows. (01:08:45)
Continuity mistake: Matrix arrives at El Presidente's house and plants a bomb on the floor. In the close-up shot, grass and weeds appear next to the bomb. These later disappear. (01:10:25)
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. (01:10:35)
Continuity mistake: After killing the guy in the watchtower, Matrix kills 2 more guys coming out of a door, plus 2 showing up from behind. The first of these two falls on the ground, but disappears a second later. (01:10:50)
Continuity mistake: While on the compound, there is a scene where some army guys are driving at Matrix in a jeep. They drive past some random army supplies and are about to surprise Matrix when he turns around and nails them with his rocket launcher. Or he sort of nails them. Actually, the army supplies that they had just passed have suddenly relocated and are crashed into by their jeep. Rewind and play repeatedly for full humour effect. (01:12:12)
Continuity mistake: The rocket launcher. It has 4 barrels. Which means 4 shots. Cindy uses 2 rockets to save Arnie from the police truck. When he is using the rocket launcher when he is saving his daughter, he fires 2 rockets. 1 at the jeep behind him and 1 at the large impassable door. But when you see him fire these 2 rockets, they both come out of the same top right barrel. Why would he need 4 barrels if the rockets come out of a single barrel? (01:12:15)
Continuity mistake: When Matrix has got the gun with an ammo feed into it, the amount of ammo left in the feed changes drastically between shots. (01:12:20)
Continuity mistake: During the shooting scene by the mansion, the same poor soldier gets killed from different angles, again and again and AGAIN.... (01:12:34)
Continuity mistake: During the long shoot-out at the compound, Arnold shoots down a whole army of bad guys. When he reaches the fountain, he shoots at about 3 or 4 people from a bird's eye view. If you watch closely, you can see one of the guards dive on the ground and play dead before Arnold's stream of bullets reaches him. Given what was happening at the time, that may have not been a bad idea. (01:12:45)
Continuity mistake: During the attack on El Presidentes house Matrix is seen using the belt fed machine gun. One shot shows him firing it apparently left handed (the film has been flipped as mentioned before) with a strap diagonally across his chest. The shots immediately before and after this he does not have the strap. A couple of shots later he is seen picking up a gun with a strap and putting it over his head. The next shot is the same one as previous but flipped back to its correct way. (01:15:33)
Continuity mistake: During the ridiculously overdrawn action sequence at the end, Arnie has a belt-fed machine gun which becomes lefty and righty through certain shots. Since Arnie isn't lefty, and it's unlikely that the army would just have a lefty belt-fed gun lying around, it's safe to say that the picture was reversed. (01:15:33)
Continuity mistake: Towards the end Arnold is firing a gun, and the length of the ammo belt changes. They show the ammo almost gone and then after an edit it's dragging on the ground. (01:16:00)
Continuity mistake: During the machine gun scene at the en Matrix has a belt fed M60 machine gun. When the fight starts, he has plenty of bullets. A few seconds later he has about 20 cm length of the bullet belt left. Scene switch - and he has more bullets. This switch between low and high ammo a few times. (01:16:15)
Continuity mistake: When Bennett holds his knife against Matrix's face the knife keeps swapping positions and also the blade appears up or down depending on the shot; despite Bennett being unable to move his arm. (01:18:10)
Continuity mistake: During the last fight, when Bennett and Matrix fall over on the platform, the gun on the floor to the right side of the screen moves around between shots, allowing for Bennett to easily pick it up. (01:18:20)
Answer: Possibly so any surviving enemies they encountered on previous missions and or tours of duty couldn't hunt them down and kill them for revenge.