Deliberate mistake: A shot of the pile of ashes from the fire wherein Cassie's body was essentially cremated showed Nina's half of the broken heart necklace sticking out ABOVE the ashes, which would be impossible. Also, a metal charm on a chain that was around Cassie's neck would not survive the huge fire or be totally clean and unscathed.
Promising Young Woman (2020)
1 deliberate mistake - chronological order
Directed by: Emerald Fennell
Starring: Adam Brody, Carey Mulligan, Ray Nicholson, Sam Richardson
Factual error: SPOILERS! While the ending of Al being arrested for murder at his own wedding is dramatic and cathartic, it wouldn't have happened that way. There's no way that the cops would have known to search the wooded area near the cabin; they would have needed to find physical evidence linking the cabin to Al; they would have needed to establish that Al had no alibi for the time in question; etc. None of that would have happened that quickly or that quietly.
Ryan: Do you want to go to dinner, you miserable asshole?