Factual error: Fitch, who professes qualifications in biology, genetics and biochemistry, says that they made Sil female because she's a natural predator and so she'd be more docile. He should retake his finals. In every single species of predator on earth - every single one - the females are the hunters, aggressors and killers. The males may be socially dominant but they are the 'docile' ones. There are no exceptions - and no human DNA was used to create Sil - they used synthetic DNA based on the instructions transmitted to them.
Continuity mistake: When the white boy is standing outside the car talking to the gangbanger inside the car, the gangster's sunglasses disappear depending on the camera angle.
Continuity mistake: At the beginning, Nix threatens young Dorthea with a real madrill, but that's all we see of it. It's never shown being put away, and it's not there when Swann and his crew break in to incapacitate Nix.
Continuity mistake: In the last scene on the roof when Holly Hunter shoots the serial killer, he falls backwards. The gun is in his left hand and the path is next to his left hand. The camera then goes to the rear of Sigourney as she walks toward Holly. Only now the serial killer is on the other side of the path and the left hand holding the gun is no longer next to the path.
Continuity mistake: The cop shoots his six shooters nine times when he's in the attic.
Revealing mistake: Brayker shoots The Collector through the eye with an arrow just after he's collected the key from Roach. You can see the section of the arrow shaft that sticks out the back of The Collector's head bend as his head hits the floor after he falls over the upstairs railing and crashes through the coffee table.
Continuity mistake: When Amanda is about to die, she gets dragged by the corn plants and they pull her shoes off. But then when she is running away she has her shoes back. Then when she slips on the pole she has socks on. (00:43:30)
Continuity mistake: When the school janitor jumps from the roof then falls on a parked car, his head is turned to the right and it's obvious that it's a dummy. Two shots later, when Dr. Chafee puts his hand on the neck to take a pulse, the head is turned to the left and the body has changed position.
Other mistake: Whenever Helen Hyde turns back into Richard Jacks, none of the clothes ever seems to rip or stretch - they both have different body types.