Continuity mistake: In the very last scene of the film Paul Newman ignores the ringing phone with Charlotte Rampling on the other end. A wide shot shows a paper coffee cup is on a table to his right, in front of the plastic lid. In close up, he reaches right, picks up the cup from out of shot, drinks from it and, judging by his arm positioning, puts the cup back in the same place. The next, and final, shot of the film is wider angle again. The lid is there, but the cup is now missing.
Continuity mistake: When Kenny Rogers gets trapped in the rest room at the beginning of the film, he pulls the knob out from the door. When this happens, the knob is on the left side of the door from his point of view. After he climbs out the window, the door has changed to having the hinges on that side and the style of the door does not look like it has a knob at all. A rest room this size would only have one door, so it has to be the same door.
Continuity mistake: When the kids are in their room, the paint brushes come flying out of the red and green cans, but as the brushes are painting on the wall, they are both covered with only red paint.
Continuity mistake: In the prologue, the boss of the bad guys approaches the window. Notice the tree casting a large shadow. He whispers "Jessie, try the door", and in this close-up there's a lot of light and it's his hand and head to cast a shadow on the wall. (00:03:15)
Continuity mistake: John is helping Mr. Nardini at the beginning of the movie. The box breaks right away and spills its content on the doorsteps, and the various items (pay attention to the blue bags of pasta for instance) shift position at every cut. (00:03:50)
Continuity mistake: When "Bruce Lee" is fighting the bad guys after he catches the poker cheater, there are multiple continuity mistakes; the bad guys are knocked atop the tables in the room but they disappear and reappear from those tables between shots.
Continuity mistake: Paul Kersey boards a bus where the line number reads 990. When he gets off, the number is 99. He could not have changed buses because the number of the bus itself remains 8027 throughout. (00:54:50)