The amount of snow covering the landscape varies dramatically from day to day and even between scenes taking place on the same day.
(at around 6 mins) When the children get off train they have no luggage. At their grandparents' house they are seen unpacking luggage.
(at around 24 mins) Flies are heard buzzing around the pile of dirty diapers in the shed despite there being snow on the ground outside. Flies go dormant or die in winter.
(at around 3 mins) When the children depart from Philadelphia's 30th Street Station the mother runs along the train as the train leaves the station. For many years, non-passengers have not been allowed into the train departure area.
There's no internet, but 2 scenes later, they're talking to their mother on the internet in the kitchen.
The house is connected to the internet, but there is no WiFi for phones and tablets to connect to. Once they find an Ethernet cable they are. Blue to connect the router to the laptop.
The house is connected to the internet, but there is no WiFi for phones and tablets to connect to. Once they find an Ethernet cable they are. Blue to connect the router to the laptop.
At 1:05 the reflection the mirror is at the wrong angle.
The blood on Becca's face when she is stabbing "nana" under the sheet is dry seconds after it appears there.
(at around 50 mins) When the grandmother laughs alone facing the wall you can clearly see the camera operator in the reflection of the glass' picture on the wall. The camera operator approaches her, followed by the actress.
(at around 26 mins) When they are driving through town, the POV is from the back seat where Tyler is sitting. Becca is in the passenger seat, and has her camera on Pop Pop who is driving. We can see through the windshield that they are going down a steep hill in town, lined with houses. Becca swings her camera around to the front and now the POV is from her camera, but they instantaneously switch to going uphill, and the houses are different and mixed with shops.
(at around 6 mins) While the children are seen riding in an Amtrak intercity Amfleet coach leaving westbound from 30th Street Station (either "Keystone Service" which goes as far as Harrisburg or "The Pennsylvanian" which goes to Pittsburgh), the coach they get off of at the Amtrak station at the fictional "Masonville, PA" is a Southeast Pennsylvania Transportation Authority (SEPTA) "Silverliner IV" regional rail EMU commuter car. SEPTA only provides service over Amtrak's "Keystone Corridor" grade west of Philadelphia as far as Thorndale (MP 35.2).