Continuity mistake: At the beginning of the wedding day scene when Mallory is throwing the red doll off the bridge, her nails are long and manicured, but later in the same scene you can see that they are bitten down to the quick. (00:19:55 - 00:21:50)
Continuity mistake: In the scene where Jack Scagnetti, the cop guy, has the prostitute in his hotel room and is about to choke her, at one point she is on top of him on the bed. When they shoot from over her shoulders she is not wearing a bra, but when the angle changes to in front of her, from Jack's view she is wearing a bra. it does this several times. This is because this scene was cut dramatically due to censorship restraints, and they had to piece it together using the same footage from different angles. Still a mistake, but there is a reason.