Continuity mistake: Fairly early in the film Spenser is beaten pretty badly by four cops which lands him in the hospital for cuts and bruises, many of which are on his forehead and left side of his face. From then on throughout the movie is face is either cut badly or not at all.
Continuity mistake: When Driscoll is walking out to his car with his son, you see the driver's side window is rolled all the way up. When he sees Spenser and goes to talk to him, the window is now rolled down, even though he didn't do anything. (01:22:00)