In the chase scene at the windmill site, the aircraft circling is (in two scenes) a single-engine, single-tail, high-wing type; subsequently, it becomes a twin-engine, twin-tail, low-wing aircraft.
The ladder appears and disappears beside the windmill door.
Despite the explicit dialogue and written appearances of the name that make it clear that the character Scott ffolliott has no capital F, the name still appears as Ffolliott in the end credits.
Carol Fisher's hair is wet after she completely submerges next to ffolliott after the plane crash. In the next shot, her hair is nearly dry again.
The establishing shot of the Hotel Europe is an outtake from the later rooftop escape sequence. Haverstock can be seen on the far left edge of the frame, next to the neon letter "H", crawling across the roof, although he is still in his hotel room at this point in the story.
The mills shown in the movie are designed in Spanish fashion, rather than Dutch.
A close-up of a telegram Haverstock receives is dated "25 Aug 1939." When he steps outside his hotel shortly afterwards, a vendor is seen selling the Evening Standard and the headline reads "Poland Invaded." Poland wasn't invaded until Sept. 1, 1939.
Most of the hotel staff that gather in Jones' room at the Hotel de l'Europe in Amsterdam are chattering in German instead of Dutch.
The butler draws the wartime blackout curtains at 10.40pm, hours after darkness has fallen.
As the purser on the ship tells John and Carol that he has no more cabins, the right side of his fake moustache can be seen sliding down. He surreptitiously pushes back it in place, but as they turn back for a second try and he continues speaking, the moustache slides down again.
When ffolliott stops his car outside the mill, he keeps moving the steering wheel as he was when the car was moving. The rear projection has stopped, but he is unsure and keeps pretending to steer.
The film is reversed left-to-right during the chess game at the police station.
After the crash, as the survivors spot the American ship steaming toward them, the matte line between the moving water and the sky can be seen.
During the scene where the passengers are scrambling to get out of the sinking clipper, a man grabs a suitcase and smashes a window, leaving a lot of large, jagged pieces of glass in the frame. He then climbs through the window and sits directly on the jagged glass.
When the young girl translates things into Dutch, the complexity of the dialogue indicates that she is fluent in the language, but her delivery indicates that she was focusing on remembering the lines rather than presenting them realistically.
Upon arriving at the windmills, and after speaking to the police, a strong wind blowing from the characters' right, blows Jones' hat off and to the left. A wind this strong should turn the windmill blades counterclockwise yet they turn clockwise as if the wind was coming from the opposite direction.
The bylines seen near the end of the film show Jones' postings from Poland and Denmark. As the film was shot before the occupations of these countries, one could not know this would happen. In any even,t as the Americans were clearly sympathetic with the Allies, the Nazis would not have allowed an American reporter in such places.
Globoidtv has noted if they didn't do the car interior custom ffolliott engraved, they'd have more budget for mustache glue.
Unrealistically, Jones is too willing to invite anyone who knocks at his hotel door to "come in" without seeing who it is first. (At least 3 times.)
When Jones and Carol are in the hotel room, she says something to him. However, no sound is heard. In the following shot, she repeats herself, and this time the audio is heard.
At 1:38:12, right after ffolliott falls through the awning, he says "Follow me!", but his lips seem to be mouthing "Come on!"
During the plane crash climax, in the montage of images after the plane hits the water, the camera tilts too high up and the lights of the set can be seen.
When Jones (Joel McCrea) and Rowley (Edmund Gwenn) get in the taxi, a crouched crew member is reflected in the side window as the cab pulls away.
When Joel McCrea and Laraine Day are getting out of their taxi, a number of behind-the-scenes elements can be seen in the reflection of the shiny taxi, including a number of crew people, a man holding lighting equipment and wires, a man holding a cigarette, a woman holding something big like a script, and a director's chair.
Despite being an ingenious camera trick at the time, it's an obvious mannequin being dropped out of the window after ffolliot's fight in the hotel room where Van Meer is being interrogated. George Sanders's character falls through the awning that breaks his fall at a completely different spot from where the dummy lands.
The streetcars are obvious dummies running on rubber tires.
Charlotte Street in London is said to be off Tottenham Court Road, whereas it runs parallel to it.
The name of London's famous Carlton Hotel is spelled correctly on the two telegrams addressed to Haverstock. However, it is misspelled as "Carleton" on the cap of the doorman who opens the door to the cab for Van Meer.
As a reporter, Johnny Jones should know how to type, but he "hunts and pecks," using only his index fingers and obviously looking for the letters on the keyboard.