The story is set in 1775. However Pugatchev invaded Iletsk as part of his uprising in 1774.
That kind of Balalaika that was played during the farmer's wedding scene appeared only in the 1880s, while the movie is set in 1775.
The first appearance of corn in Russia was in the 1810s, while in the movie a Cossack is holding it in 1775. While the first time Russia got in contact during the Russia-Turkey-War 1768-1774,it is unlikely for a Cossack to have it.
It is mentioned that the story is set in 1775 and based on the view it is obviously in Spring. The mentioned "Pugatchev-Uprising" of 1773 ended in January 1775, Pugatchev himself was killed in January 1775. Nevertheless in the movie he is still alive.
During the entire movie the name of the Cosak leader Yemelyan Pugatchev is pronounced incorrectly. It should have sounded like "Pugatchov" instead.