Revealing mistake: In two scenes - first when Harry Boland is getting on a train, and next during the game which is machine gunned by the authorities, overhead DART (Dublin Area Rapid Transit) electric train lines are visible over the railway. The film is set between 1916 and 1922, and the DART started operations in 1984.
Revealing mistake: There's one head of police who, during his short stint in Dublin, pledges to introduce 'Belfast efficiency'. Shortly after that he is killed by a car bomb. However, when the bomb goes off there's a split-second shot where the car is empty although three men had just gotten in, and the driver who was starting the car is a rather crude dummy. (00:46:05)