The periscope, Richmond's wristwatch and 303 rifle, and half the equipment carried and worn by the soldiers are actual items from World War One and World War Two.
The location stretches over 100 meters of trenches, only a small portion of which was used in the film.
The whole film was shot over two nights.
Only three explosions throughout the entire film are real - the remainder are CGI.
The film is set during the Battle of Bullecourt, in May 1917.