Factual error: The Germans in the castle are using Bell 47 helicopters which, apart from being manufactured by the enemy, did not even appear until after the war.

Factual error: In the courtyard of the castle there is an anti-aircraft gun. You could probably not find a worse place for a gun like that even if you tried (except maybe if you put it inside, in a windowless room). In the position it is placed it can only fire at targets directly ABOVE the castle. What you want to do is fire at targets BEFORE they reach the castle. It would be better if they placed it on the roof, or even near the village below.

Continuity: When Smith is driving the bus, there are at one point several bullet holes in the bus' windscreen and in the next shot they have vanished.

Revealing: When the bus is being pursued, Smith steers it to trip several prepositioned explosives that blow up trees to block the road. In order to by pass a downed tree the Germans push a motorcycle around it, and you can plainly see that the tree was cut by a chainsaw.

Revealing: When the Allies are dropped from the plane into the snow and they find the dead soldier. Watch close, because the dead soldier blinks his eyes...

Revealing: As the spy troupe prepares to leave by airplane, a Kübelwagen with soldiers comes up, which Burton shoots with his MP40. As the car bursts into flames, the driver and passengers are revealed as dummies, since no one could or would sit around quietly while they were on fire.

Continuity: Smith puts on one glove just before he hops onto the cable car with the two German spies. The next shot shows him with two gloves on.

Continuity: When Mary and Schaffer are firing the MP-40s from the back of the bus, a shot from outside of the bus shows the rear windshield broken/cracked one way but in the next shot from inside the bus looking out the rear windshield is broken/cracked differently.

Revealing: After Smith and Schaffer are captured and while they are being transported by car, Schaffer pushes one of the guards out of the car and a struggle begins which causes the car to crash. After the crash, the body of the guard that was pushed out of the car magically appears about 50 feet behind the accident (just before the crash there was no body).

Factual error: The aircraft at the Luftwaffe airfield at the end of the field look like US Harvard trainers.

Visible crew/equipment: In the scene where the Germans are pursuing Richard Burton's escaping party as they make their way towards the aircraft waiting for them, you will see the first of two pursuing German Kubelwagons being hit with machine gun fire and flipping. When this happens, you will see a cable used to flip the vehicle on the bottom left side of the screen being quickly retracted as it becomes detached from the Kubelwagon's axle.

Continuity: As the stolen bus ploughs through the German airfield Smith yells to Schaffer, "Take out the control tower," so Schaffer and Mary point their guns high and start firing. There is a long shot of bullets strafing the control tower, glass shattering and the traffic controller falling backwards as he is hit. It is followed by a quick close-up of him in perfect health, shouting into his radio, then being mowed down by the stream of bullets.

Factual error: As the coach moves through the village near the end of the film, it drives past a tracked vehicle. The vehicle is a Hotchkiss LPz, a type of armoured personnel carrier not produced until the 1960s.

Continuity: When Schaffer and Smith commandeer a motorcycle and sidecar, one shot shows the MP-40 slung over Schaffer's neck and laying across his lap, while in the next shot it is slung over left shoulder and hanging down his side.

Continuity: During this sequence at the radio transmitter in Admiral Rolland's headquarters, whilst the Admiral is attempting to regain contact with Smith, Colonel Turner is seen in the background, smoking. At the beginning of the sequence, one shot shows him holding a cigarette between the fingers of his right hand. After a cut back to the Admiral, the next shot shows Turner holding the cigarette in the fingers of his left hand.

Continuity: When Schaffer climbs the rope into the castle, he reaches the top of the rope, grabs the window sill and starts to pull himself in. It then cuts to inside the room where Schaffer can be seen outside holding on to the top of the rope and then grabs the window sill to pull himself in, again.

Continuity: When Richard Burton's character and the others have completed their parachute jump, they find Sgt. Harod dead in the snow. Richard Burton says at first Harod broke his neck on landing, but later said to his trusted comrades Harod was murdered after landing. Since he was murdered by a member of the landing party there would be tell-tale footprints of the murderer in the virgin snow around Harod's body, but there are no foot prints around him at all.

Factual error: In the scene where Clint Eastwood's character is sneaking up in the German soldier in the radio room in the castle, you see and hear the soldier changing radio station channels. Most of the music you hear playing on the radio is distinctly a 1960's style easy listening music and not 1940's music.

Continuity: The car that Schaffer and Smith are riding in with the Germans is launched in the air by hitting a pile of snow and then comes to a sudden stop by hitting a pile of gravel where the Germans are killed. What happened to the pile of snow when Schaffer and Smith push the car backwards?

Continuity: In her castle room, Mary lays all the sticks of dynamite on their sides in the suitcase. When Smith opens the suitcase in the meeting room after they got the names of the spies, the dynamite is now standing on end.