Character mistake: As we know throughout this movie series, Michael's middle name is Audrey. However when the doctor is typing Michael's release form, he types his middle initial as "M".
Suggested correction: Michael's middle name is only mentioned in an additional scene that was added to the television version of the original Halloween. If going by the theatrical versions Michael's middle name was never known, so not really a mistake.
Doctors at a sanatorium would certainly know Michael's middle name. It's been on file for decades.
Character mistake: Watson says that there are fifteen windows on the front of 221B Baker Street, but if you look, there are only twelve.
Character mistake: Phoebe gets hit in the head with a tree branch but she puts her hand on the opposite side she was hit on.
Character mistake: An unloaded automatic pistol is much lighter and balanced differently than a loaded one. When McClane hands "Bill Clay" (Gruber) the empty pistol, a terrorist of Gruber's credentials should pick up on the odd balance (I notice that difference, and I very rarely even pick up a gun).
Suggested correction: This presumes that a person can notice the difference between a fully-loaded pistol versus a pistol that is empty, which makes sense. However, it would be much more difficult for a person to tell that a gun is completely empty versus one that only has one or two bullets loaded. Since Gruber has no way of knowing his ruse didn't work, he doesn't believe McClane would have given him a completely empty gun. He obviously believes there is at the very least one bullet in the gun. He's not planning on getting into a shootout with McClane, he is just planning to threaten him and he certainly doesn't need a fully loaded gun to do that.
Suggested correction: It's easy to tell the different between the weight of a loaded vs. unloaded pistol, but given Hans had never held the pistol before, he had no way to compare the weight. Unless he regularly handled that particular model of pistol (unlikely, given his pistol is a completely different make and model) he would have no point of reference.
Character mistake: When the little boy is reading his report about Abraham Lincoln, he states that Lincoln was born in a log cabin in Illinois. Lincoln was actually born in a log cabin in Kentucky.
Character mistake: At the football players funeral, the guy on the left is still breathing, despite being dead.
Character mistake: When Mick arrives at walkabout hotel, Nugget introduces himself to Mick as if they have never met before. Yet in the first movie, Nugget is asking how Mick is getting on in New York. It may be just a case of over familiarity by Nugget but it doesn't make a lot of sense.
Suggested correction: It's quite possible that they haven't met, but Nugget's heard about Mick, e.g. from the people in the bar, stories, etc. Having no doubt heard so much about Mick, Nugget probably feels like he knows him, at least enough to ask how he's getting on.
Character mistake: Buster and June are watching TV, and he says, "Hey, Julie" (the actress' real name). (00:08:07)
Character mistake: When Nico comes out of the parking lot and gets caught by the police, right before he gets in the van and is patted down by the police officer, the police officer says, "she's clean", not "he's clean."
Character mistake: When Frank opens the present in his office and finds the picture frame from his brother inside, he reads what is supposedly written on the frame out loud: "To Frank, the best brother a guy ever had. Merry Christmas." However, instead of Merry Christmas, it says Love, James.
Character mistake: When Dr. Walker and Michelle are dancing at the club, the people around can't help but stare at the camera.
Character mistake: As the prosecuting DA finishes his statement about Kenneth Joyce to the Jury, he tampers with the Jury by assuring them they won't believe Joyce's witness testimony. And somehow the judge does not catch this or ignores it completely.
Character mistake: On the way to Jerusalem, Poirot says that "that man, Weizmann, put it rather well the other day, before Lord Peel's commission", and gives a famous quote about the world being divided in 'two places' for the Jews (those where they are not allowed to live, and those they cannot enter). The movie takes place in May 1937, and Chaim Weizmann's quote is from November of the previous year. 6 months are hardly "the other day."
Character mistake: Cindy tells Greg she hasn't worn curls for 12 years. This is incorrect because in the original series, she changed from curls to braids by 1973 and then to straight hair by 1974. This story takes place in 1988 so technically, she hasn't worn curls in around 15 years (not 12).
Character mistake: Kathy Ireland as Wanda speaks mostly in a slightly squeaky voice. But in one scene she uses her own regular voice.
Character mistake: Mr. Phillips told Michael (Danny) that he'd like him to apply for "early admission" to Julliard. Michael was a 17-year-old high school senior and had not yet auditioned for Julliard - the audition is to occur when a student his age is "entering 12th grade in the Fall of the academic year for which he is applying." It was too late to submit an application and an "early admission" was not possible at this point. (01:08:42)
Character mistake: Mac's cousin says that even if Nick wasn't a cop, he'd have to hate Mac's guts. He says that Mac wears a Rolex and Nick wears a Timex - not true. Nick is wearing a Rolex, also.