Continuity mistake: Simi enters the bedroom and the upper half of the bedspread is smooth. Aunt Claudia is holding a book with both hands, so she is not touching the bed. The front (somewhat aerial) view of the bed shows that the upper part of the bedspread has multiple ripples. (00:17:55 - 00:18:42)
Continuity mistake: The blood that was on Leonard's right cuff disappeared and re-appeared a couple times. When he was cutting the bloody suit, the blood on his cuff was gone. When Leonard looked into the briefcase, the blood on his right cuff re-appeared, but was no longer there when he was sewing the suit's sleeve (or thereafter). (00:31:38 - 00:32:40)
Factual error: Doctor Key tells Mary, "If you pose a threat to those around you, we will be forced to keep you here [hospital] longer. That means your son will be placed in foster care." Family members, such as the grandmother and uncle currently taking care of Tony, are preferred before placement in foster care. Foster care is usually considered among the last resorts, not first, and only when there are no suitable family members or significant others to provide temporary care for a minor. [SPOILER: It isn't known that the grandmother and uncle aren't biological relatives.] (00:29:15)
Continuity mistake: Jackie holds her pen as she takes notes. Next, her pen is set on the legal pad and her hands are on her lap (below the table and pen). The camera returns to Jackie, and she continues to hold the pen as she takes notes the whole time. (This allows for other questionable variations that could occur off-screen, if enough time.) (00:38:57 - 00:39:29)
Other mistake: At the end the camera bulbs would not work as they are electric. This is proven when the music starts after the creature leaves the area. (02:01:00)
Continuity mistake: While Ben is talking to Eloise, his glass of alcohol is about three-fourths full, but when he lifts the drink to his mouth, his glass is almost empty. (00:07:20)
Continuity mistake: The gingerbread man cookie falls into the coffee cup, and the top is barely below the rim. Looking into the cup, the top of the cookie is much further down but does not fall this fast. The coffee cup is about half-full. Jackson takes a drink. The cookie does not interfere with the flow of the coffee into Jackson's mouth. When Jackson lowers the cup from his mouth, there is no visible cookie. (00:08:20)