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: In the final scene in which a man is shot in the airport (part of this scene actually recurs throughout the movie), the psychiatrist woman leans over him to hold him as he dies. From one angle, he reaches up to her face and his hand is clean. In the next angle, his hand is covered in blood as he touches her face.
Continuity mistake: This is the car chase scene, where Ralph Fiennes and Angela Bassett are in a limo being chased by two bad cops in a pickup. Early in the scene, you have the view from inside the pickup when it rams the limo from the rear passenger side, and you can clearly see bullet holes in the glass and rear of the limo (no weapons fired yet). Then a few seconds later in the scene, you can see the rear of the limo with no damage. Moments later, you see one of the cops firing an automatic weapon, and subsequently witnessing the holes being made in the limo.
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.
Continuity mistake: When J-Bone is coming down from Heaven, the lift he's on stops quite a way off the ground, and moves when he steps off it. Yet when he, Johnny and Jade step onto the lift, it seems to be on the ground as it doesn't move. It couldn't have been lowered, as we would've heard the noise of the motors.