Continuity mistake: Hooper wears rimless eyeglasses, with the arms either attached at the upper corners of the lenses or at the sides of the lenses. If this didn't happen between shots within the same scenes, it could be presumed that Hooper has two different pairs of glasses and switches between the two, but they do indeed change between shots, such as when Mrs. Kintner slaps Brody, or even later, on the Orca. (00:36:05)
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?
Factual error: During the scene where it shows people all over the world, just before the shuttles take off, it is daylight everywhere. It would actually be dark or near dark in parts of the world.
Revealing mistake: The kid in the wheelchair is playing a Game Gear with no game in it.
Factual error: Regardless of how bad an attorney he is, Ned Racine must surely know that his acquittal for murder is a shoe-in. It's very doubtful that the prosecution would have even held out for remand in his case, and in fact they probably would not have even charged him in the first place. The fact that his fingerprints are on Edmund Walker's glasses is irrelevant. He and Racine were seen in public together, notably in the restaurant, and he freely admits to being in Walker's house. He could have handled Walker's glasses on any one of these occasions. The conversation Racine has with Ted about building the firebomb cannot be used in court, as Ted fires Racine as his lawyer at his second meeting; everything from the first is covered by attorney-client privilege. Maddy obviously isn't around to give evidence, and the yearbook entry Racine finds throws suspicion on her (and away from Racine) immediately. There are no witnesses and no forensic evidence, in fact there is nothing to support the prosecution case except a vague suspicion based upon his having had an affair with the widow-to-be. No court in the US would entertain the case for a minute.
Plot hole: The "death" of the three astronauts and the requirement to then fake the whole scenario of the failed mission was obviously unplanned - it came about because of an unexpected computer glitch which reported that they had burned up on reentry, causing a mad scramble to cover up the fake mission and kill the astronauts. Obviously it was planned to have the astronauts "return" to Earth as heroes after their supposed trip to Mars, maintaining their deception (under threat if necessary) for the rest of their lives. One problem. Every scientist on earth would be champing at the bit to get their hands on a sample of Martian rock. Samples would be worth billions, worth far more than Moon rocks are worth today. How was NASA going to explain they didn't have any? They could not possibly fake the rocks - Martian soil and rocks would have a number of identifiable characteristics that a smart first year college student could identify. Using Martian meteorites collected from the Earth's surface won't work, either - prolonged exposure to the Earth's atmosphere would leave tell tale weathering and chemical changes that would be instantly detectable. NASA have painted themselves into a corner and that is not something they would have failed to realise well in advance.
Continuity mistake: In the opening scenes where he gets his mustang back, he hits the guy who comes over the roof and busts the windshield, but in the very next shot the windshield is pristine. (00:07:45)
Continuity mistake: Mr. Furlong pushes Zeke into the fishing tank and it breaks, soaking him from head to toe with water. Moments later they are walking out and he is dry.
Revealing mistake: When the kids are burying Gus, his supposedly dead face flinches when they shovel dirt on him.
Factual error: Mel and Goldie board a ferry. A visible sign states 'Detroit-Racine Ferry'. Detroit is on the east side of the state of Michigan but Racine, Wisconsin is west of Michigan, across Lake Michigan. The only water route to get from Detroit to Racine would be to circumnavigate the entire state of Michigan.
Other mistake: At the end of the film when they arrive in NYC looking for the library, we know that they survived because they are inside with a roaring fire burning. But where is the smoke up above, as Jack Hall approaches? There must be a chimney, or else they would have all died of asphyxiation.