Even though the view through the portholes is black, on the exterior shots of the Columbiad, it's sky blue.
At the beginning of the film, Barbicane's speech before the Armaments Club lasts 4 minutes, but the hands on the clock behind his head show no movement.
Just before the spaceship is launched, someone shouts that the red warning rocket has been fired. But when the rocket explodes, its color is white.
The acceleration tubes don't move as fast in the close-up shots of them as they do in the long shots of the entire mechanism.
When they discover they're orbiting the moon, Nicholl remarks that soon they'll "feel the heat, the terrible heat of friction" - an impossibility in the vacuum of space. BUT! In the era on which the film takes place, it could not be certain that the moon had no atmosphere. Therefore, assuming that the Moon has an atmosphere that could generate friction was not a crazy idea.
The free-wheeling "beds" that support the occupants of the acceleration tubes should turn so that they are oriented away from the axis of rotation due to the centrifugal force. Instead they always hang "down", even when the tubes are shown to be spinning rapidly.
As Victor (Joseph Cotten) takes his place at the top table a clock is finishing striking 12. There's one on the bureau behind him showing 12 o'clock but in 5 minutes of screen time it's still striking 12.
This film states that its story happens in 1868 and yet it shows Victor Barbicane meeting with President Ulysses Grant. Andrew Johnson served as President from April 15, 1865 to March 4, 1869.
In the beginning, it is announced that the story begins at 97° W 42° 30" A day's and night's journey from New York. In the 1860s, the travel time is closer to 6 days to this location.
Despite dire warnings of death should occupants of the projectile NOT be in the "acceleration tubes" upon launch, no explanation is offered as to why Virginia isn't turned to goo by stowing away in another room.
During the meteor shower, sparks from the passing meteor fall through the main viewing port into the ship, revealing the absence of glass.
The rocket exhaust and flames curl upward around the base of the projectile instead of streaming out to the rear.
For the shot of Virginia looking out of the porthole, the placement of her hand reveals that there is no glass in the porthole.
On the exterior shots of the Columbiad, the arm holding up the model is visible.
The second clock on the screen at launch does not match the audio several times.
The location given is mostly flat farmland with very low rolling hills in all directions. There are no mountains visible in the distance as shown when they are building the projectile or launching. There is no large town with huge mansions as shown at Barbicane Station.
The three Power X flares Barbicane flashes to signal Ben and Virginia that he and Nicholl are alive on the Moon are clearly spaced too far apart on the surface of the Moon for him to have been able to travel the distances involved (as he had no means of transport at his disposal other than by foot).
Barbicane's intention had been to land on the moon and return to Earth. However, he required a massive cannon to launch the ship from Earth. How did he expect to take off from the moon without having a giant cannon in place there?
Early in the banquet scene, when Barbicane is addressing his guests, the shadow of the boom microphone is clearly visible on the wall behind him. (Though as noted in the trivia section, it would not have been visible in theatres, as it would have been projected at 1.85:1. The version shown on TV is open-matte at 1.37:1.)
As Joseph Cotten is greeting his international guests and says, "Therefore, I shall get straight to the point..." the shadow of the boom mic is visible on the wall.
When Nicholl asks that they toast death when drinking their celebratory glass of wine, Barbicane looks askance, telling Nicholl that "his sense of humor leaves a great deal to be desired," but acquiesces, saying reluctantly, and with obvious distaste and puzzlement, "Very well - to death." Yet despite his supposed dismay at Nicholl's morbid toast, Barbicane himself makes sarcastic remarks about death no fewer than four times throughout the voyage: at the start (telling them wryly that in a few minutes they might be dead); while explaining the acceleration tubes ("You'll have just eight seconds to brood over that error - after that you'll be dead"); when Nicholl is eating ("Cheer up - there's a strong possibility that you'll never finish that soup"); and after explaining his now-aborted plans for the sale of Power X ("Actually, we should all be dead already").
Despite wearing a dress and skirt with petticoats and a bustle, Virginia fits into the space suit with no 'bulge' to show the gathered material so her legs would fit the legs of the coverall.