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)
Plot hole: After the first death, Ian is in the office and after the conversation with the girl the scene starts to speed up, indicating that time is passing by at a fast pace; yet even with the rapid time change, the sun's rays that pass through the office never move or change in any way as it should.
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)
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.