Continuity mistake: There's an oscillating fan near the ceiling that alternates between running and not running from one cut to another in one scene.
Continuity mistake: In the scene where Terry is in the coop with all the dead pigeons, he is holding a dead pigeon in one of his hands, and he grabs the hook with the other hand. But when he stands up the pigeon and the hook have switched places.
Visible crew/equipment: In the opening scene, Edmund O'Brien grabs a bookie, drags him down an alley, and around a corner. When they round the corner, the entire boom and mic cast a huge shadow against a stark white wall.
Continuity mistake: After the operation to change Vic Brady's face, the first time the bandages come off, the scar on his forehead runs diagonal from the top of his nose to well above the eye. However when he's shot by the pool, the scar runs laterally across the middle of his forehead.
Continuity mistake: At one point bus driver Frankie Howard shins up a signpost to read road directions in the fog. The sign says WET PAINT and he slides down with his uniform jacket streaked and ruined. However, several minutes earlier, as he leans forward to peer into the night, Howard is already wearing the paint-stained jacket.