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.
Visible crew/equipment: There is a shot in front of a sliding glass door. If you watch the glass and not the actor, you can see the mike boom and cameraman reflected in the glass.
Other mistake: In the beginning of the film when you're introduced to the younger, humanoid Sil in the laboratory, an extreme close-up of her eyes and face clearly reveals the young actor's contact lenses.
Other mistake: When Sil jumps through the hotel room wall, Pres fires two shots from his Glock and then gets in the elevator. In the elevator he drops the magazine and his Glock has the slide locked back showing the magazine is empty. The man is an acknowledged expert in special ops (Indeed, the fact that he changes magazines in the elevator demonstrates his preparedness. He wants to face Sil with every bullet he can, he doesn't want to be even two short.) He is going up against an extremely dangerous extraterrestrial life form that has already killed several people. There is absolutely no way he would be carrying a weapon that was not fully loaded.Grumpy Scot
Factual error: At the end when the oil in the cavern is burning there is no sign of smoke. With a fire as large as it appears to be, everyone in there should be choking to death, yet they don't even seem the least bit bothered. Forest Whitaker should have also been roasting over the flames, yet he is unscathed.