Continuity mistake: In the scene where Doug and his brother are talking outside the cemetery, the zipper on Doug's jacket goes from being almost completely zipped to about halfway zipped without him touching it.
Continuity mistake: In the scene in the laundry room Claire thinks back to the bank robbery when she would have gotten blood on her blouse. The recall shot shows her standing in the bank wearing the blouse. In the original shot during the robbery she was laying on the floor wearing a black jacket and would not have gotten blood on the blouse under the jacket. (00:06:00 - 00:20:00)
Suggested correction: Blood could have seeped through her jacket to her blouse.
Continuity mistake: When the gang use the black car, they have a collision with a police cruiser and the driver's side headlight and wing is crushed. During the chase that follows, however, there is a brief shot of the car going around a corner and the headlight and bodywork is now intact again, and in the next shot is back to being damaged.
Continuity mistake: During the robbery at Fenway Ben Affleck is unshaven when dressed as a Boston Police Officer, yet when he begins his escape as an EMS worker he is clean-shaven.
Continuity mistake: In the scene where Doug and Jim go beat up two strangers, who Claire accused of harassing her on her walk through the projects, the door is closed. Right as Doug gets up to leave, the door is open, and the door is closed again when Jim shoots the bully in the leg and they leave the apartment together.
Continuity mistake: After the Fenway robbery, while Agent Frawley is after Coughlin the sun changes between shots, and then again when Coughlin is leaning against the mail box.