Continuity mistake: The small wound below Jack's left eye increases and decreases size through the film.
Continuity mistake: When Jack tosses Samantha's phone out the car window (when leaving the prep school), it breaks into three pieces, two on the walkway and one onto the grass. When The Hunter walks up to the phone, all the pieces are near each other on the walkway, and they are on the other side of the walkway than the two pieces originally landed. (00:47:35 - 00:49:15)
Continuity mistake: In the beginning in his first fight Jack gets a wound on his right cheekbone which disappears in the next days.