After the diamond is stolen, Inspector Farraday tells a gang of reporters in his office that the diamond is worth $500,000. However, the promotional sign that sits outside the exhibit states, "Valued at $200,000."
When Blackie returns to rescue Runt with Farraday as he comes to the top of the stairs the crook pulls the trigger on his gun. You can hear the hammer click as it strikes an empty cylinder. When the camera cuts to a different angle the hammer is cocked as if the trigger had never been pulled.
When Chester Morris hails a taxi you can see three banks of lights shadowed against the taxi.
Approx 25 min: as sister "Eileen" goes from her bedroom back to the living room, we can see the shadow of the camera-man reflected on the right hand living room wall.
After Blackie, (dressed as a messenger), delivers the "Blue Star of the Nile" diamond to Inspector Farraday, he tells him where the bad guys are holding "The Runt" hostage. Before leaving, Farraday uses the telephone to call for backup, but the phone is upside down. He's speaking into the earpiece and the telephone cord is coming out of the part that he has to his ear.