To the modern discerning eye, the use of miniatures is apparent in some scenes. If one looks very closely at the first scene, ambulance trucks driving up a winding mountain road will be seen to be well crafted miniatures.
A night attack is shown. During World War I there was very little flying at night and the night attacks that did occur were limited to big cities. It was almost impossible for a plane to attack specific targets in a large city, so effectively attacking people on a road in the dark was not possible, and did not happen.
When Frederic places the ad in the newspaper, he writes that he will be at a hotel in Stresa. But when they show the awning of the hotel, they misspell Stresa by adding an extra "s".
The film is set during the First World War, but all the characters wear 1930s fashions.