Character mistake: In a scene when Watney is recording his video log, he imagines what would happen if his pressurized shelter suddenly would break. He concludes that he would implode, but the correct wording would be explode.
Character mistake: Near the end of the movie, when Newt and Minho and Frypan and others are all being checked by WCKD's scanners to identify the subjects. Minho is called subject A4 when he is really subject A7, subject A4 is Chuck. Newt is also called subject A6 when he really is subject A5, Subject A6 is ALBY.
Character mistake: When Gaby's car becomes wedged between two buildings, she says, "Good plan. All we have to do is get over two twenty-foot walls and a minefield." While minimal backstory is given, I think it reasonable to assume that she has lived in what was East Germany all her life. It is thus highly unlikely that she would express a measurement in English units (being bilingual doesn't mean you automatically convert measurements). She would have said something like "six meters."
Character mistake: When in the car both are talking about a scar on his back. He is telling her he was in Serbia chasing a man all over the tundra. Mistakenly thinking of Siberia instead. (00:41:13)
Character mistake: When writing in his ledger trying to reach 1 million oysters shucked, Adam's numbers do not add up. After 998,246 the next entry is 996,691 followed by 1 million. Did he mysteriously un-shuck 1,555 oysters?
Character mistake: During their bickering about the coffee, the idea is that the officers just drank some coffee made from beans coming from excrements of rhesus macaque. That's how the civet coffee is made; macaques merely chew and spit the beans, they do not 'process' them (that'd be the kopi luwak that he references immediately after). (00:27:00)
Character mistake: Sciarra's (pronounced Shara) name is constantly mispronounced Skeeara, even by Italians like the priest at the funeral.
Character mistake: Nob Hill is mentioned as the highest point in San Francisco. It isn't the highest point. Mount Davidson is.
Character mistake: In the final fight at Goodison Park, the commentator says 100,000 people are in attendance. Capacity of Goodison Park is 40,000, and even allowing for people in the "pitch" area around the ring there's nowhere near space for that many, unless there was another layer of fans standing on people's shoulders.