Goofs

On the boat in the harbor, after Inspector Ahmet tells Dr. Petrie to contact the Home Secretary's office, the sky and weather shift abruptly from blindingly sunny and clear to dark, overcast and windy with choppy seas (as if it were about to rain) for the shots of the scarf.

When Fu Man Chu's soldiers attack the castle for the first time, the defenders bayonets are clearly made of rubber.

The first scenes where Fu-Manchu is directing the sinking of the liner were the final scenes of a previous Fu-Manchu movie: The brides of Fu Manchu, where he shots his lieutenant who was trying to stop Fu Manchu surpass the maximum of the machine.

One of the major characters, played by Maria Perschy, is called 'Ingrid' in the film, 'Anna' in the printed synopsis, and 'Marie' in the end credits.

When the soldiers attack the castle, they shoot the gate guards with submachine guns and fire a flare pistol, but the other guards around the castle grounds do not hear or see anything.

At the start of the film, Fu Manchu says, "In the tropical waters of the south Atlantic, my hand stretches out to turn water into ice." The newspaper report Nayland Smith reads says the liner struck an iceberg in the Caribbean, which is part of the north Atlantic.