Revealing mistake: After Lansbury makes her clothes start to move, her nightgown attacks someone and you can notice the strings that make the gown move.
Revealing mistake: When the platoon hear the church bells, they mistake it for the invasion signal and construct a barricade across the high street. If you look behind them you can see cars parked on the road in the distance that date from well after the 1940s.
Revealing mistake: When Von Richthofen is shot down and crash-lands in the combat zone, German and British soldiers arrive and fight for possession of the Red Baron's plane. It is strange, though, that the German soldiers fire British Lee Enfield rifles instead of the German Mauser Gewehr 98.