Continuity mistake: Blood from Tom's shirt's elbow when he is attacked by Rachel appears and disappears randomly between shots.
Continuity mistake: The blood pattern on Anna's shirt changes from when she stands up from Tom's body to the police station.
Continuity mistake: When Tom drags Megan after she has knocked her head, for a brief shot the blood on her face disappears.
Continuity mistake: When Tom is lying dead, the blood on his shirt is completely dry. A frame later, when Anna approaches, it is soaking wet.
Continuity mistake: Before Rachel and Scott fight, he offers her a drink. Her fringe swaps from messy in the side angle, to perfectly brushed in the front angle.
Continuity mistake: When Tom smashes the mirror, all the bits of glass fall off. In the next angle some reappear.