Goofs

During the ski chase they use cross-country skis but during the downhill shots the skis have become downhill skis which are wider and the heel is clipped in.

When the saboteurs approach the factory they lower themselves off steep cliffs into the gorge by rope, after the sabotage they hike back the same way.

When Knut offers Rolf the toothpaste in the darkroom he places it behind his back. A cut to Rolf over the shoulder of Knut has the toothpaste still extended in his hand. The next cut has Knut with his arm behind his back again.

Kirk Douglas says every time you do something 12 people are shot. In the previous scene the german officer orders the execution of 15 people.

After shooting Jensen, Dr. Pedersen tucks his pistol into his belt with the grip to the right. When the German doctor lifts his jacket, revealing the pistol, the grip is to the left.

After the commandos blew up the canisters in the factory containing the heavy water and got away there was no shooting involved because the German guards couldn't find the switches to turn on either the floodlights or the alarm.

In one shot Anna spots a wild animal and says: "Look, a rabbit!" There are no wild rabbits in Norway, and the animal was a hare (possibly a mountain hare) with white winter fur. A Norwegian used to the wilderness would never make such a mistake (nor should actress Ulla Jacobson, she was Swedish).

Anna, Pedersen's ex-wife, still wears her wedding ring -- but she wears it on the wrong hand. Germans and Scandinavians wear their wedding rings on the right hand.

Ar the beginning of the film the German officer demand 10,000 pounds of heavy water from the lead scientist. A German officer would never use the imperial measure of pounds - it would be kilogrammes or litres as it is today.

In the darkroom scene Dr. Rolf Pedersen is about to print a black/white image yet we can see a lot of white light everywhere, therefore the paper will have fogged up long before he starts. A darkroom should only have red light in it.

When Rolf and Knut finish blowing up the factory where the heavy water is produced they both escape. Rolf is then injured and captured by the Germans and eventually escapes to rejoin Knut but how he escapes is never explained.

Knut's escape takes place off-screen but this does not constitute a plot hole.

In the opening scenes where the Nazi command convoy is driving along the cliff road, the Mercedes cars are right-hand-drive. Mercedes cars built for Germany were always left-hand-drive, so one can only assume that the car used was one built for the Austrian, Swedish or UK market. A Mercedes from Austria or Sweden could easily be found driving in Norway.

In the last shots of the lifeboats on the lake, the downdraft from the rotor of the camera helicopter is clearly visible on the water.

When they meet Jensen on the plateau, Knut Straud is meant to be wearing skis. He manages to turn completely around without the usual action of lifting his skis up to the vertical (the shot of him is only from the waist up) that is necessary to turn around while standing still wearing skis.

When the town is under attack from bombers, anti-aircraft guns are seen firing at the planes. They rotate on their turntables at an unrealistic speed and after firing, the barrel wobbles in all directions. A real cannon would recoil along its axis and the muzzle perhaps point further up momentarily. This suggests they are plastic models.

When 'Uncle' is resisting arrest and reaching for his shotgun, the wooden beam it is hanging upon clearly moves.

The bombs are set to detonate when the ferry is at the deepest part of the lake.

However, a long shot of the lifeboats and the smoke from the sunken ferry are shown as being very close to the shore, not more than about 100 yards or so.

All the women in the movie wear their hair in very 1965 styles; none of them has anything resembling a 1940s hairstyle.

Character Anna Pedersen in a couple of scenes is wearing a knitted sweater known as Mariusgenser with characteristic pattern (made for brothers Marius and Stein Eriksen). This pattern was introduced for 1952 Winter Olympics in Oslo, and did not exist at the time of the war.

The tiny clip of archive footage at 51 minutes into the movie shows a Short Stirling bomber towing a Horsa glider. The movie is set in 1942 but both aircraft carry invasion stripes used during the Normandy invasion in 1944.

When the Germans arrive to arrest 'Uncle', as the truck passes the window, the crew are clearly visible in the window glass.

After Rolf kills Jensen and skis away, a shot of Jensen's body is shown. Moving shadows of a crew member are visible over his body.

Early in the movie Dr Pedersen enters a boat in Oslo harbor to go to Trondheim. Nobody would take a boat from Oslo to Trondheim (a long trip lasting several days) as there is a direct train lasting 8-10 hours. In any case there was never a regular boat service from Oslo to Trondheim. Later Pedersen says he is going to Kristiansund, a town south of Trondheim.

When the Resistance men go off to attack the factory, Knut declares that they are wearing British uniforms. In fact they are not.