When they entered the house, the police tape between the two pillars leading to the front door is broken. When they open the front door to exit the house, the police tape is suddenly complete again.
When Maddy is walking down the stairs with the key, it is her left foot that is bandaged and bloody. Almost at the end of the stairs, it is her right foot, which is bandaged and bloody.
When Madison and Jake is in the nursery trying to call 911 and Jake takes the phone, the back of the phone is twotone silver and a bit black metal.
But then there's a closeup and the phone is plastic and all black.
The outside of the house is covered in graffiti yet the inside is pristine, not even dusty or cobwebby, even though the house had been abandoned for more than 20 years.
It's quite odd for such a large house so go abandoned like that even if a tragedy has occurred in it, and for Madison's guardians to not make any attempt to retrieve her belongings or sell the house and its fittings to raise money for the girl. And unless it was sold, there should be no reason for Madison to have to break into a house her family owned, or at least for the group to be worried about getting caught.