Continuity mistake: Arnold is handed an upside down photograph of his friend's witness. As he views it the photograph is correctly oriented without being turned around.
Continuity mistake: Arnold goes to the gay bar to solicit the help of the guy he saved at the beginning of the movie. The guy is wearing a white shirt and a vest black/gold lamay. During their conversation he takes off the vest, then it cuts to another bartender. When it cuts back the guy has the vest on, another shot and the vest is off again.
Continuity mistake: If the bullets from the super gun move at just under the speed of light, how come the bad guys can't hit him or the girl? The bullets would arrive almost instantaneously and that would mean minimal compensation for them running. Plus the guy had them locked on when he shot.
Continuity mistake: Even aside from the ridiculous recoil that a railgun would cause (yeah, I know they don't use gunpowder, but there's got to be SOME opposite movement, surely), how come when the darts (bullets, whatever) go straight through people, they still get thrown backwards? The passage straight through them means minimal energy being transferred to them, and as such they shouldn't be hurled backwards that much.
Factual error: The bad guys are able to close in on Vanessa Williams at the end by tracing the signal Arnie sends to her beeper. How could they triangulate her location through a passive, receptive device? Maybe if it was a cell phone, but not a pager.
Continuity mistake: When Arnold gives the girl a credit card, he slides the card to give her credit, but the magnetic strip is facing the wrong way.
Continuity mistake: At the end, right before the train crashes into the limo, the back of the limo is facing the blocking rail. However, after the train hits the limo, the front half of the car is right next to the rail, and the rear half is nowhere to be seen.
Continuity mistake: After the court scene, when Arnold and Vanessa are making their exit toward the van, they get in, the van explodes and the camera pans to the underside of the van, showing Arnold pulling a manhole cover closed. The manhole cover was not there when they showed the van from a distance and they didn't have enough time to get in the van and escape through the bottom. Also, because several seconds passed before he closed the manhole cover you would have to assume he was still above ground when the bomb went off, therefore killing him.
Continuity mistake: When Arnold is hanging under the parachute the plane tries to hit him and he shoots at the plane, breaking the glass of the cockpit windows. When the plane lands later on, the windows are intact again.
Continuity mistake: Arnold dives to save the girl under the lid of a fridge. When all the drill bits are shot at him with his hand above the fridge door, none hit his hand. But in the next angle one penetrated his hand. Then in the next scene, when he's driving the van with both hands and when he swipes the credit card the wound appears and disappears.
Continuity mistake: It's astonishing that Arnold still has a gun after he jumps out of the plane since he didn't holster it before he jumped. Still he pulls it out of his holster before he shoots the plane and during the shootout in the zoo. It's also pretty strange that this weapon, a Desert Eagle .357, fits into the holster, since Arnie's first pistol (the one the young Marshal was shot with) is much smaller. Another fascinating thing about the gun is the fact it has a maximum capacity of nine bullets plus one in the chamber but Arnie fires about 15 or 16 times.
Revealing mistake: When Arnold is in the plane and throws his belt buckle-knife at the traitor. The next shot shows that it bounces off and continues to spin. Pretty obvious that it's held up by a wire.
Revealing mistake: When Arnie jumps from the plane, notice the stunt double. He weighs about half of what Arnie would, and has no muscles.
Factual error: When the bad guys are looking through walls with the rail gun's scope the light on the gun shines through the wall, but in real life it doesn't do that unless you are looking through a window.
Factual error: After removing the first parachute, Arnold uses the emergency one. However, when he deploys it, he is only a few hundred feet off of the ground. At this height, the parachute would do nothing except possibly snap Arnold's spine.