At 42.58 Farraday and a uniformed officer arrive at Blackie's apartment building, with Blackie right behind them. At 48.26 the officer is looking out a window to the street with Blackie driving off, but the police car is gone.
Blackie uses a round-back chair to lock Cecelia in her wall bed. When the police arrive and free her, they remove a different square-back arm chair.
On the second note Blackie leaves Faraday written in soap on a mirror, he is seen emphatically making two exclamation marks at the end. But, when finally shown, the mirror has three exclamation marks.
Blackie knocks the head off the real mechanical man with a pitched ball; in the subsequent long shot, the head is intact.
Story takes place in Coney Island, New York BUT shots of moving cars show mountains in the background. Even in 1941, Brooklyn New York had no mountains.