Plot hole: There is a barely credible explanation for the fact that a guest cannot be injured or killed by being shot in Westworld, but what about the vicious fistfight we see in the bar? People are injured or killed in bar brawls all the time, and this one was incredibly violent. How do they prevent guests from being injured or killed by the cutting and stabbing weapons we see in Medieval and Roman World? Guests are supposed to fight each other, not just robots - they cannot be 'programmed' to lose! Delos is going be sued into bankruptcy within a week of the first guest arriving. Quite apart from the legal position, think about the bad publicity! Who is going to pay the huge fees demanded by the parks owners when the media is constantly reporting on the guests who wound up dead or with life changing injuries?
Visible crew/equipment: After Callahan removes the bomb from his mailbox, he looks up at a man on the nearby stairs. As a car drives by on the street, the lights from it cast the shadow of the boom operator onto the wall.
Continuity mistake: At one point D'Artagnan reaches the Duke of Buckingham, who is on a hunt. He has just killed a stag and his hands are covered in blood. D'Artagnan rides up and offers him a note from Queen Anne. He wipes his palms with a cloth before he takes the note, but his hands are still covered with blood up to and above the wrists. When he reads the note, he and D'Artagnan take off on foot for his castle where they go into a private room behind the walls. Suddenly it is apparent that his hands are perfectly clean right down to his scrubbed fingernails and, without explanation, the plot-heavy sequence continues.
Continuity mistake: The swords of the animated statue of Kali are different from the swords used in the close-up fight scenes.
Other mistake: In the intense outdoor battle scene at the end, when Bruce kicks a guy in the face three times in a row, one of the extras in the background cracks up laughing.
Factual error: On the night of 19 October 1933 the railroad workers begin betting whether A-One will make it to Portland on the 19. A quick closeup of the money changing hands reveals the $1's to have the Great Seal reverse (introduced in 1935) plus the motto IN GOD WE TRUST (introduced in 1957). Also, the green-seal Federal Reserve Notes and the red-seal United States $2 notes are of the types first introduced in 1934.
Revealing mistake: When the Grand Ville turns onto the street where the children are playing, it clips a parked car as it makes the turn. This is the same car that later gets its driver's door ripped off by the Grand Ville just before the police give chase. It was repainted red for the second scene, but note the same dent in the right fender as before.
Continuity mistake: Flatfoot Rizzo comes out of the door at the top of the building with an agile tumble. The black sailor shoots him but he's out of bullets. In the close-up with the gun that clicks empty, suddenly large shadows appear on his chest, which were not there when he was shooting in the same spot and pose. (00:05:05)
Other mistake: Throughout the whole scene when Black Caesar is wounded by the Irish hitman several passers-by can be seen looking directly into the camera, and in many shots people are crowded together on the sidewalk watching the filming. Conversely, the hitman fires a big and loud revolver in the middle of a crossing with dozens of people and cars in close quarters, and nobody bats an eyelid. (00:03:00)