Revealing mistake: Technical Glitch: In the opening scene before the opening credits. The British are being run out of one of the last remaining fields in France. The Sergeant is burning the "lame ducks" when German planes attack. A German plane attacks almost directly toward the camera, you hear machine gun noises but no effects. Next a plane attacks from right to left, you hear machine gun noises and see the effects indicating the bullets striking the target. After the second plane has gone you see the effects of the first planes attack.
Revealing mistake: The shot in the station is somewhat revealing, not only a modern diesel train (as already reported) in 1914 but also a third electric rail. (01:05:15)
Revealing mistake: When the Remagen bridge is bombed, it is obvious that the bomber planes shown have been taken from several shots (possibly also from an earlier film) and the shots were superimposed. Also, the bombers appear transparent, and the background sky's color is unnaturally strong, too.