
Continuity mistake: When Arnie comes home after killing his workmate, he pulls Sharon Stone to the floor. From one angle his hands are on her shoulders, from another they're on her elbows. (00:23:45)
Factual error: Throughout the movie, whenever the domes are breached (which happens much too often) it is said that there is only vacuum outside. But Mars has an atmosphere. Its thin and mostly CO2, but it's there.
Suggested correction: While it is not a true vacuum outside the domes, it's around 1% of Earth's atmosphere. The effect of a dome breach would be close enough to a true vacuum to the people affected.
Suggested correction: "Vacuum" is a colloquial way of saying low pressure, just like the 'vacuum' you use to clean the house creates a low pressure to cause suction.
Suggested correction: It's possible human colonization of the planet affected the atmosphere.
If the Martian atmosphere ceased to exist, the sky would be always black, never red as seen in the movie (Mars' sky is actually a butterscotch color during daytime and bluish during twilight).
Factual error: When a person goes out into space, their eyes wouldn't be sucked out, their cheeks puffed, etc. They would have about 10-20 seconds of useful consciousness, when they could get back to a safe area. Even after that, they'd still be alive for about a minute, although unconscious. The only major problem that being in space for about half a minute might cause is rupturing the eardrums and possible blindness (although the eyeballs wouldn't be graphically sucked out). NASA's studies on this go back as far as the 1960's and were used by Stanley Kubrick during the making of 2001: A Space Odyssey. (00:03:50 - 01:43:20)
Continuity mistake: If you look closely at the position of Arnie's arms while still on the 3D screen, they are in a different position when he breaks through. (00:30:00)
Continuity mistake: In the airlock where Benny fires his machine gun at George, the lock handle behind Benny rotates on its own. (01:23:05)
ryguy_1983Visible crew/equipment: When Quaid and Melina hop into Benny's cab and are being chased by Richter, watch Benny. During the shots where the perspective is from behind Benny, you can see that it is a stunt driver in the car. His head is shaved neatly, yet Benny's hair is curly and frilly all over. (01:11:00)
furious1116Revealing mistake: Right before Quade jumps on the train to get away from Richter, he uses a gun to break one of the train windows. His gun barely (if at all) touches the window and it shatters. (00:31:40)
NickiRevealing mistake: When Arnie blows the old lady disguise mask on Mars Immigration, they shot him and the dome crashes. Right after the soldier gets sucked out of the room, some extra comes rolling and kicks the camera. (00:47:05)

Continuity mistake: When Doug is running from the bad guys after finding out what was going on from his "wife", he tucks his big gun in to his jacket pocket. When he is running through the scanner, that big gun is now in his pants. (00:28:15)
Lynette Carrington
Revealing mistake: In the scene in the Mars Air/Spaceport, the troops are wearing Casio scientific calculators on their wrists. (00:43:50 - 00:46:55)

Continuity mistake: In the scene where Quaid unfolds a flyer for The Last Resort, he unfolds it with the flyer image facing the camera. When the scene cuts to him looking at it, the flyer image is facing him. (00:52:00)
Revealing mistake: When Doug and Melina are being chased by the drilling machine, it punches through a wall. When the machine comes out again it pulls some rocks with it, a very large one hits Melina and she doesn't even flinch, obviously because it's a fake rock. The size of rock should have knocked her to the floor or potentially killed her.

Revealing mistake: When Quade shoots Dr. Edgemar, Lori yells "Now you've DONE IT.", and the wall explodes, which is plainly made of foam. Many of the pieces of 'wall' tumble lightly across the floor. (01:05:40)
NickiContinuity mistake: When Melina comes to the rescue of Doug, she starts shooting his captors. He drops to the floor, then in the next shot, he drops again. Doug also wakes up on top of a dead guy who had landed much further away from him before. (01:04:15)
DazContinuity mistake: During the hallway fight sequence between Lori and Melina, we see Quaid in the background aiming a machine gun - just as Melina gets kicked in the back. But a few seconds later, Quaid reaches for the same gun a second time. (01:07:40)
ryguy_1983Revealing mistake: During the scene when Quaid is escaping from Harry and his men, he slams two guys into the concrete wall behind him. The "concrete" wall shakes when the two men hit it. (00:22:25)
Floyd1977
Continuity mistake: When Quaid enters George/Kuato's private room in the rebel base you can see George's desk has a different arrangement from one shot to the other with Quaid's gun disappearing, a blue container swapped with a white on, the computer's screen having a cable plugged in or out and other objects moved around. (01:16:00)
TheSliderContinuity mistake: In the scene where Quaid takes out Lori with a bullet to the head, she lands on the floor in such a manner that allows blood to run across the right side of her forehead. A few shots later Melina pushes Lori out of the way, repositioning the body on its opposite side. But once Richter discovers Lori moments later, blood is only visible running across the left side of her forehead. If anything, there should be blood running from either side of the bullet wound. (01:08:10 - 01:09:05)
ryguy_1983Continuity mistake: When Arnie enters the hotel room on Earth, he receives a phone call from a man with a suitcase who tells him to look through the window. While Arnie is approaching to the window, we can see in the display that the mysterious man is looking to his upper right. In the next shot, when Arnie is looking through the window, we can see that the hotel room is located at the man's left side. (00:35:10)