Factual error: The movie is set in 1948. When Easy first visits Albright about the job, Albright throws some $20 bills down in front of him. The top bill bears the signature of Treasury Secretary Nicholas F. Brady, which appeared on paper currency from 1988 to 1993.
Continuity mistake: When the father pulls the cover off the toy castle that's Drosselmeier's gift to Marie and Fritz, there are no soldiers visible in or on any of the towers. But when there is a close up of Marie asking how Drosselmeier got in, there is a soldier on the tower next to her head. Then the camera cuts to a different angle as Drosselmeier approaches and the same tower is visible, but with no soldier.
Factual error: In the opening scene with Doug Masters flying in Russian airspace, he is to be escorted back to American airspace by MiG-23s. But in fact the two planes that show up are F-4 Phantoms. When the "MiG" fires a missile, you see a completely different plane. Best I can tell, that is not a MiG either.
Factual error: In two, maybe three scenes, there are ring-necked pheasants. One is early in the movie as the Jameses ride past a butcher shop where ducks and pheasants are hanging up for sale. One is mid-way in the movie in the scene of the house- or barn-raising and big picnic. The movie supposedly took place in the mid-1870s. Pheasants were not imported to America from China until 1881.
Continuity mistake: When Angus and Yellow reach the lake, Angus's face is tore up pretty bad, but after they cross the lake and go to the building on top of the mountain his face is almost completely free of any injuries.
Revealing mistake: At the cemetery, a reporter nudges a headstone and it moves, revealing it is fake.
Audio problem: On the video version, in the barbecue scene, the band starts playing the slow song. The camera is on Eddie and his daughter and they are dancing. If you look closely, the male singer in the background is shown standing on stage and just holding his guitar and not singing, even though the vocals can be heard. In a later shot, he is actually singing. Still later in the scene, he is shown just standing on stage and not singing.
Factual error: At a very early point in the film, the King says something along the lines of "....and these are your playmates". In the background is a horde of 17th century ladies boating on the Achille Duchenne water parterre at Blenheim Palace. The palace wasn't built until the late 18th century, and the parterre was not designed until 1925.
Visible crew/equipment: When Jeremy impales himself on the silver ritual knife, watch as the "knife" bends under the weight of his body - an obvious rubber prop.
Continuity mistake: When Tommy is buying the right to perform the Parker brothers' material, Tommy asks to see the material that he's just bought. He stands up and turns the chair round so that it's facing away from the table. The shot then changes, and he turns the chair round so that it's facing away from the table again.
Continuity mistake: During the camping trip, when Chevy and JTT are talking about the guys who have come to kill Chevy, JTT's feather changes colors from plain black to black and white.
Factual error: In the movie, Wild Bill has a shootout with the bad guys in the stables. He is holding two colt revolvers, each having the capability of holding six rounds each. However as a safety precaution, only five rounds were loaded in the revolver with the hammer resting on an empty chamber as a safety. Therefore, he could only have ten rounds total from the two colt revolvers. He fired far more than ten rounds without reloading.