Continuity mistake: The size of the knife wielded by the girl during the junkie Ian scenes changes significantly from a large butcher knife in the kitchen, to a small steak knife once outside when stabbing the evil girl. (00:45:30)
Revealing mistake: During Ian's double-kill moment in the morgue, you can see the prosthetics on his chest crease once he drops to his knees for the fatal blows. (01:14:00)
Continuity mistake: Standing in the subway talking about what the creatures were, the blood from the infected tract wound from the heroin needles is completely gone, as well as the entire wound itself. (00:46:30)
Jenny: Are you all right?
Ian Stone: Yeah, aside from the sudden desire to slit my wrists I think I'll make it until Monday.