Revealing mistake: More rounds come out of the Vulcan than are carried by real Harriers.
Audio problem: When the helicopter is following "Carlos the Jackal" and Jamie Lee, it's hovering really closely, yet they never hear it. But you can hear it as they are being taken from the trailer home. (01:00:05)
Continuity mistake: During the bridge sequence, the limo drives through an area that is on fire. After emerging from the fire, the passenger side headlights are shown to be blackened from the smoke and heat. Further down the bridge the headlights are shown to be clean and new looking again. (01:56:40)
Continuity mistake: After the shootout in the restroom, close to a hundred rounds were fired, all from LOUD guns, yet when Arnold and the terrorist are running through the mall and out the window, people are standing around in the stores, like they never heard a thing. Heck, that AK-47 would even be heard by the people outside on the street. The only one to hear anything is the guy on the toilet. (00:33:30)
Continuity mistake: When Harry is racing the police horse through the park and hotel you see the end of his reins flip up several times. They are regulation length leather reins. Yet when the horse stops and flips him off over the edge of the building, suddenly the reins are about 10 feet long and much thicker. Also, in reality, the reins would probably have snapped or the bridle would have broken had 200 plus pounds hit the end of them at that speed. (00:34:45)
Revealing mistake: In the scene where the harrier shoots a missile and blows up the bridge you can clearly see that it's all miniature, but if you didn't know, you could tell it by the crash barrier that is obviously made of some sort of rubber - it bounces up and down during the explosion (you see it in the frame where the car crashes down on the bridge again). (01:54:10)
Factual error: In the amount of time it took for Arnold to exit the lake and infiltrate Khaled's party, the mere temperature in the mountainous region would freeze the hole over long before the patrolling guard would come across it. It might not be fully frozen, but enough to be mistaken for being normal to the casual observer.
Factual error: When Arnold's harrier hovers up and a terrorist has to adjust the focus of binoculars, it shows Arnold's face. Being so close, there would be no way binoculars would have a clear view of his face, maybe a blurry eye at best.
Continuity mistake: When Arnold is talking to the horse after being pulled up on the roof by the reins, his right hand moves from holding the reins considerably far from the horse's mouth to right up next to it between shots. (00:40:35)
Revealing mistake: In the scene where the limo crashes off the bridge after Hellen Tasker has been picked up in the chopper, the camera pans back to show a strut of some sort is falling from below the limo. (01:58:35)