Other mistake: In the book Hazel is reading near the start of the film, the word 'to' is used 4 times in a row.
Other mistake: In the flashback to Richard's childhood, when he looks from the door at his dad randomly shagging a party guest, the door appears open wider in the POV than it is in the other shots, where the opening barely fits his head. Besides, with the head in that position, he wouldn't see the door handle as shown. (00:02:00)