When Amelia leaves the tent during the rain and sleeps outside, she awakes the following morning yet the ground appears dry with no sign of the previous evening's rain.
As Amelia crawls toward the back of the covered wagon, from behind her, one sees her reach the edge. Then from outside the wagon, she again is seeing crawling over the same distance a second time.
In the 40th minute Amelia carries her case in one hand and a hot tin of tea in her right. The manner in which she holds the tea changes in between shots, yet she could not have done this without either the use of her other hand, or at least resting the cup on something.
Amelia awakes outside covered with snow which fell overnight. The position of the snow on her face changes between shots.
Considering how under-dressed Amelia is for the snow and cold, she and the boy would not likely have survived, especially when others with additional clothing and shelter had perished.
She could not possibly carry all the possessions she has, solely in her one case.
Amelia lies down atop the bloodied blanket, yet her dress doesn't absorb any - none - of the blood.
In the 39th minute when Amelia is in the covered wagon that comes under attack, an arrow lodges in the cover. As the cover is extremely thin, basically a sheet, the arrow would have gone straight through.
After escaping her pursuer, Amelia has a cut on her leg but her dress is neither slashed nor bloodied.
The boots that Amelia takes off the dead cowboy have zippers on them. The film is set during the California Gold Rush. Between 1848-1855. Zippers weren't invented until 1893.
The piano that was found in the woods near by the abandoned wagon had a company insignia of the Thompson Piano Company, Chicago. The Thompson Piano Company, however, was not founded until 1870, after the main onslaught of Oregon trail travelers between 1811 and 1840.
The boots Amelia removes from the stage coach have zippers, which were not yet invented.
When Amelia is dragging Levi's body to bury him. You can clearly see a crew member behind the wagon.
After she put her husband on the quilt to drag his body away to bury it, 2 legs are seen behind the wagon train wagon wheel. Since she is alone, these legs were one from the crew.
When Amelia and Levi are in the tent, The boom mic can be seen on the right side of the screen when we see a close up of Levi.