This is a rather unusual movie, telling of the complete loss of religious freedom during the French Revolution (i.e. the State suppresses the Church), and some Frenchmen who would not stand for it.
The movie is unusual in that all the parts are played by young people under the age of 21.
This doesn’t necessarily take away from the intensity of the movie, however. Take a look at the trailer: The War of the Vendee.
There are many more movies from various parts of history (especially the 20th century) that could be made on this topic. Will we start to see more now?
Fr. Z’s review explains more about the unusual casting.