Factual error: When the first robot is trapped in the lift, the teenagers shoot the propane tanks on top of the lift in order to get them to catch fire and explode, killing the robot. However the teens are firing pistols or shotguns, and these do not contain incendiary ammunition, which is what is required to make the propane to catch fire.
Factual error: Petrol cans sold in shops are always empty. They would never contain petrol when bought. There would be nowhere in a shopping center to get petrol exactly for health and safety reasons.
Revealing mistake: The laser blasts the robots fire instantly exterminate or destroy most everything in their path. However, when the guys are shooting at them during the mall blast-out, the lasers suddenly don't do much damage at all.
Continuity mistake: Allison stands six feet from the doorway as she tosses the lighted flare into the paint shop, at the killer robot, and then everything explodes, and she runs off left. But moments later, after the fire and smoke has died down, the camera pans back from the doorway wreckage, and she is suddenly lying wounded in the same spot where she threw the flare. When she should have been long gone out of there.
Visible crew/equipment: The fake spider that suddenly swings down in front of Allison in the hallway, and the one "thrown" at her as she walks through the mall at the end, are obviously prop pranks, as you can hear a fake laughing in the background during the latter. Very badly covered up by barking dogs and something whining.
Continuity mistake: The perspiration on the girls faces changes while they are up the air vents. In a few shots sweat is dripping from their faces, but in other shots their faces are completely dry.
Continuity mistake: Just before the second technician is killed by the robot's pincer stabbing him through the magazine he is reading, if you look closely you can see the holes in the magazine made by the pincer in previous takes of the scene.
Continuity mistake: When the robots are chasing the girls, the girls are all carrying make-shift Molotov cocktails made out of petrol cans with a rag in the neck. Suzie is hit in the leg by a robot and falls to the ground. The robot then fires a laser at the petrol can by her, causing it to burst into flames, which cover her too and burn her to death. However, when the camera pulls back, we see that her petrol can is mysteriously intact and untouched by the flames.
Other mistake: Walter Paisley is cleaning the floor and encounters the first robot. The whole reason the robots are patrolling at this point is that the shopping centre is supposedly closed to customers, as it is nighttime. However in this scene you can see quite a few people shopping on the upper tier of the mall above Paisley.
Other mistake: When Allison "crashes" into the paint store near the end, she merely leans against the glass and it instantly shatters, which would not happen without her swinging something extremely heavy or sharp against the glass.
Other mistake: When Mike and Leslie are fooling around, another moment cuts back to them now sitting up in bed, and her mouth covered in perfect silvery lipstick as she rummages through her purse for smokes. No way did she had time to reapply her lips after just having sex.
Other mistake: When Allison runs into the pet store to escape the killer robot, she passes by a tarantula aquarium on her right, before crawling in to a hiding space below some dog cages. When the killer robot crashes into the pet store after her moments later, it knocks over two aquariums on the right, and one on the left.
