Plot hole: When Alana is backing up down the hill after running out of gas, she passes a single story house on the left which has an obvious motion detector light on the front of the house that triggers the light to turn on as her truck passes by. Motion detectors of that type were not around in the seventies.
Plot hole: Antoinette Lilly makes headlines as being murdered and her husband is charged and sent to a criminal asylum...despite the fact that no body has been found and no one has even bothered to go to the hotel or town she was last at to investigate whether or not she's alive or dead. Not believable.
Suggested correction: John was framed by Antoinette's step-mother (who stood to gain Antoinette's inheritance). People have been arrested for murder without a body being discovered first though. Additionally, we find out that the lawyer who helped framed John also paid him to confess to the crime and admitted to being mentally unstable. So nobody was even trying to look for Antoinette.
Plot hole: When Buckaroo is speaking with the president via video call (with John Parker by Buckaroo's side), New Jersey is explaining the reason humans can't see the aliens from planet 10, is a result of bacteria produced by the aliens which is then absorbed by humans via their olfactory senses, affecting their cerebral cortex. If this is the case, why doesn't the president see John Parker in his true alien persona. He can't smell him through the television. (01:04:50 - 01:05:40)
Plot hole: When major Singleton challenges Brant Royle to a duel with single shot pitons, he fires one pistol, and leaves the other pistol on the bar. He then goes into his carriage and shoots himself. He only has the pistol that has already been fired.
Plot hole: Gail and Katie talk in her shed about Guy's phone call. Katie says "I didn't lie about anything", which is a really odd non sequitur. All Gail said was "I just got off the phone with Guy Morgan. Your phone. He just loved that little demo you left him. I have underestimated you. It'd make me proud if I actually cared about you." Nothing about it prompts a response like that, except the plot point that Gail told Guy that Katie lied about it appropriating Bev's demo. But Katie does not know that fact at that point. (00:21:00)
Plot hole: The Thorwalds were supposed to be in the apartment for only six months according to the lease, their phone number wouldn't have been published in the phone book for such a short lease.
Plot hole: Viola convinces her mother she is staying at her father's house for two weeks, but who covers for Viola with school administrators? As far as we see in the movie, Viola is not reported absent from either Cornwall or Illyria (a transfer would explain not being reported absent from Cornwall). Administrators or class mates at Cornwall would find it strange that she stopped showing up, since soccer training had already started. It is unlikely Viola officially transferred to Illyria, since her parents would have to sign off on that, or at least start paying her tuition to a different school. Viola could have called in sick to either Cornwall or Illyria, but this is never addressed in the movie. And if the soccer program at either school started before the official school year, it would make no sense for them to have a biology class with students not enrolled in athletic programs at Illyria.
Plot hole: When the host family picks up Finley, they tell her that they have just inherited a bed-and-breakfast. Later, Nora tells Finley that while she was cleaning up "in here" she found Finley's brother's notebook "under the dresser." Later it's revealed that Finley's brother had visited stayed with the host family several years earlier. His notebook would not have been in the "recently inherited" bed-and-breakfast.
Plot hole: After Eli's guardian is hospitalised for acid-burning his face, Eli hears on the radio that they can't ID him because of his facial wounds. When we see him in the hospital however, only half his face is injured, the other half is fine which would make a mirror composite easy for lab techs.
Plot hole: Kate could not get Leo's photo in order to get his passport.
Suggested correction: He was rich and famous, they had no problem finding information about him online, so could have found a suitable photo online (photoshopping it if needed).
Plot hole: The plot that a piece of the Roman spear that pierced Christ ends up in a hidden Mayan temple in the Amazon (which is nevertheless still full of gold etc.) makes no sense.