Revealing mistake: After the accident with the German car crashing into the pile of snow in which the Germans were killed, Schaffer first hangs an MP40 on his shoulder and then somehow pulls up a body with only one hand. And with the changing of the grip, (from chest to legs) the 'body' stands on his own feet to give Schaffer the time and opportunity to do it properly. (00:50:10)
Revealing mistake: 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.
Revealing mistake: 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 mistake: 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). (00:49:25)
Revealing mistake: When the cable car is seen in long shot coming down from the hill (carrying the film's heroes) it is painfully obvious that while the cable car is real enough, the mountain behind it is fake.
Revealing mistake: The team parachuted onto a mountain top while it has been snowing for some time, but when they go looking for Harris the missing radio operator, you can see footprints in the snow.