Continuity mistake: In the scene where Cohaagen's team break into the train station, some of them enter through the top windows. It was previously established that the atmosphere in that area was unbreathable, but Cohaagen and the rest of the crew move around just fine without the need of a mask, even though the windows to the outside are broken.
Factual error: The movement of "the fall" as depicted in the movie is utterly impossible. The distance between the Colony and the Federation is about 6 000 miles, and the trip takes 17 minutes. This means that the fall would have to travel at an average speed of 20 000 miles per hour, or faster than the space shuttle in earth orbit! Given that it accelerates at the start and decelerates at the end the maximum speed would be even higher, and the acceleration required would be considerably more than 1G. Not only does the fall move at much slower speeds in all the scenes showing its movement but this speed would only be possible in a vacuum, which is not the case since people actually move outside the fall while it is moving.
Continuity mistake: At the final fight on the 'Fall', Doug affixed explosives at every brace. After crossing the Earth the top of the 'Fall' becomes the bottom- as well the explosives. But in the movie they explode again at top braces.
Continuity mistake: Toward the end of the movie when Cohaagen and Quaid are fighting on top of The Fall, Cohaagen has taken a few punches and a foot to the face by now and has a cut on the right side of his face. After a toss, Cohaagen comes up with a knife and begins a short monologue with no sign of the injury, then it briefly comes back and then disappears again.
Continuity mistake: In the first fight scene between Lori and Quade, Lori's pony tail miraculously disappears after she is thrown into the ceiling over their bed. The frames go between the two hairstyles during those for seconds.
Character mistake: When looking at the various items in his safe deposit box, one of the passports has the name Henry Reed. However the serial at the bottom of the passport is mistyped as REED/HENTY.
Continuity mistake: In the scene where Hauser and Melina are running through the elevator shafts, as Lori attempts to enter the shaft, one of her synthetics is destroyed by an elevator, thus leaving her with 2 of the original 3 synthetics. Just before the one of the synthetics hooks on to the bottom of the elevator to follow Hauser and Melina, there are 3 synthetics with Lori. Where did the extra one come from?
Continuity mistake: During the chase scene after Quade escapes his apartment it is raining, but Lori's hair switches between dry and wet continuously as she is chasing him through the rain.
Plot hole: Hauser did not have to have his memories erased and become Quaid. He was already trusted by Melina before becoming Quaid and he was already set to meet with Matthias. Then, after needlessly giving his top agent the memories of a factory worker, the Chancellor pairs Quaid with his number two agent, Lori, yet keeps her in the dark about the Quaid/Hauser connection - even though the goal should be for Lori to let the other side find Quaid.
Deliberate mistake: In the finale, the main characters exit 'the fall' and climb up the outside of the vehicle. As the vehicle is travelling at thousands of miles an hour, they would have surely been sucked off instantly and most certainly would not have been able to maintain a grip on the ladder rungs as they climbed 'the fall'.
Continuity mistake: When Lori is chasing Hauser and Melina in the car and he cuts off his gravity to drop to the floor. When they crash to the floor Melina's head is facing down, but when they flick between shots her head is facing up.
Plot hole: When the rebels find the message in Hauser's mind, Cohaagen and his men appear almost immediately. The rebel base is supposedly miles from civilization in a poisoned city. Plus the signal in Hauser's head was the signal the revealed Mathias' location. It should have taken hours for them to arrive.