Continuity mistake: When Lt. Snyder breaks the phone booth window with his gun and points it at Hooker, Hooker's hat falls off. Yet in the next shot over Lt. Snyder's shoulder you can see that Hooker's hat is back on his head.
Continuity mistake: Rizzo breaks up the rumble at the pizza joint; in the wide shots when he keeps the goons in check, there are several more unperturbed bottles in the shelves behind Manomozza than in close-ups. Some of the bottles that were in the side shelves in fact have inexplicably moved onto the center one. (00:11:25)