At around fifty-five minutes, Amy meets her boyfriend and she has no shoes on. After she leaves him, she is seen with shoes on.
When the father is sitting at the kitchen table surrounded by whiskey bottles, all of the liquid in the bottles is clear. Whiskey is not clear. Also, he is later shown guzzling clear liquid out of a Jägermeister bottle. Jäger is not clear either.
The Roman Catholic church is the only Christian faith that still performs exorcisms. The priest performing the exorcism reads from a King James Bible. Catholics do no observe the King James Bible, as it is a Protestant Bible.
When the burglar breaks into the basement, it is nighttime. When they switch to the interior, it is obviously daytime outside, with sunlight streaming in through the windows.
During the phone conversation between Amy and her boyfriend, her phone is clearly turned off, whilst his is on the menu screen. However, his is briefly on the call screen during the distance shot.
In the opening scene, the killer swings the hammer at the lady at such an angle that they would hit very low on the body. When the camera cuts back to her, she has been hit in the head.