When Laura investigates the "abandoned baby" in the subway car and finds a doll, the doll is lying with its head to the south. In the flashback to the woman leaving the doll, the doll is laid down with its head to the north.
When Parker is supposedly dead, one of his legs twitches.
At about 22 mins, Laura visits Parker's grave, but just a minute later when she reaches the baby doll, the shadows on the house indicate that hours have passed.
When Laura first picks up the baby to shake the rats off, it's obviously a doll stand-in.
When she is in the subway car, it is not moving. We hear sounds and see light flash in the background. The subway car in an old non-air conditioned car. The last of these cars were retired several years ago. This car is most likely located at the Brooklyn Transit Museum.
An easily distinguishable reflection of a man's head is visible to the left of Laura, in the section of darkened glass, while she is in her closet selecting a garment to wear.
At about 1:09, Laura calls the university and asks for Jenny Foster, the former coworker of the cashier at the supermarket, but the cashier never told Laura Jenny's last name. Maybe she got it from the diary.