Character mistake: When Malloy first visits Frannie in her apartment, he says the girl was killed on the 15th, but when Frannie is in the cop car for the first time, Malloy's partner says it was the 11th.
Character mistake: When Jimmy kills Dave, he says that he killed Just Ray when his wife was pregnant with Brendan, but she was pregnant with Ray Jr (Brendan's brother).
Suggested correction: Jimmy says pregnant wife, little Brendan.
Suggested correction: My father used to tell stories about his nieces and would constantly get their names mixed up. People often get siblings names switched around, and that is when they are in their right mind. Jimmy had been drinking, was still emotional over his daughter, and was telling the story with full intention of murdering Dave within minutes. Fully understandable that he would make this rather common error.
It might be understandable, but not so much within the context of this movie. Would the writer deliberately include in the script that a character will use the wrong name because it does happen sometimes in real life? Maybe if this were a movie about dementia or "Grumpy Old Men", but it doesn't seem to fit in this movie. [I know - not all elderly people have memory problems or lapses.].
Character mistake: The letter from the FBI containing the results of the blood and semen test is filled with numerous typos. First, on the line "Subject: Result of examination requested", the word "examination" is misspelled "examnation." Second, the term "DNA instrumental analyses" has "instrumental" incorrectly spelled as "insrumental." Third, the line "Reference: Letter dated October 21, 1987", has the word "dated" misspelled as "dateed" and the month "October" misspelled as "Octorber." (01:58:35)
Character mistake: There's no way that using a regular needle and thread to sew up that wound would work the way it's shown. Anybody who knew what they were doing - which John Cusack is portrayed as knowing - would also know that using unsterilized materials and instruments without a sterile field from an uncleaned massive open wound is a great way to kill your patient.
Suggested correction: The main plot of this film takes place inside the head of a murderer with dissociative identity disorder. The fact that stitching up a wound in that matter wouldn't work is irrelevant to the fact that it is how Malcolm is playing out the scenario in his head.
You're making a good point to invalidate a "character mistake", but couldn't the entry be reclassified as a "factual mistake" and stand as written?