Other mistake: When the main guy and the blond-haired woman investigate the house of the guy who got hanged in the very first scene, October goes outside to smoke. She is seen in a construction site. Later, when they go to find October, we discover that the site is way down the street. I don't know why she decided to stray so far from the house to the site.
Other mistake: When October uses the nail gun to try and ward off the evil woman, she points and shoots it like a normal gun. However, as a safety precaution, nail guns have a mechanism that requires it to be pressed against something in order for it to dispense nails. Therefore, October couldn't have used it like she did.
Other mistake: In the closing credits, "Stunt Double October" is misspelled as "Stund Double October".
Other mistake: After Phin gets run over by the carriage, one of the cops wants to try out the game for himself. We first see him reciting the prayer and it cuts away to Hutch and the other cop talking. In less than 10 seconds it goes back to the cop playing the game and he's already in some room in the game. It would have been impossible for him to go through that prayer, customize his character, get in the house, learn the controls, and get to that specific room in that amount of time.