Continuity mistake: The subject of the email from Barry S. first reads "we need you", but after opening it reads "RE: No subject"
Other mistake: During the newscast after the girls are taken 3 photos are shown. Casey's photo looks to be a screen shot of her in the car whilst the abduction was taken place This is an impossible photo to have on the news.
Character mistake: The Master of Psychology Degree from Tulane University has a spelling mistake. School of Political Sciences is spelt 'Scineces'.
Continuity mistake: Late in the film, after The Beast emerges, he partially devours two of the young girls like a ravenous animal; yet, when he catches up to the third girl, Casey, a few moments later, The Beast has no blood on his face, body or hands. Furthermore, when The Beast corners Casey in the cage, he presses his face between the bars, and we see no blood on his face. The camera cuts to Casey then back to The Beast, and now streams of blood are running from his mouth and down his chin. The camera cuts to Casey and back to The Beast once more, and now we see no blood on his face.