Goofs

When Gregers and Edvard are ambushed, Gregers shoots the fake informant with a Walther PP, but a moment later, he's armed with a Colt Model 1903.

When the Nazis were marching on Karl Johan's Gate (Oslo) in June 1940 the trees in the park were leafless suggesting early spring or late autumn.

In the scene in the hospital in Stockholm where Max learns that Gregers is dead, his tank top moves between the far left and the far right of his shoulder between shots.

The Norwegian saboteurs used so-called 'Limpet Mines' to sink German ships. Such mines contained only a small amount (4 kg) of explosives and were placed on a target ship's hull beneath the water line. In that position, even a small hole can do a lot of damage (in part due to the water pressure surrounding the hull). In the movie, though, more than once, we see giant, flaming explosions when the mines detonate. Those types of pyrotechnics simply do not occur with the use of small, below-the-water-line Limpet mines.

At the first sabotage action in the film we see a brightly lit Oslo harbor. In reality, however, a blackout was enforced in case of allied bombing raids.

In many of the scenes where Max and his collaborators are riding bicycles, the bicycles are 1955 or later vintage with features that were available more than a decade after the end of world war II.

In the scene were Manus is introduced to "the gang" in 1940, Jens Christian Hauge is introduced. He actually was in jail at the time and joined the resistance later.

Early on in the film Max Manus meets Jens Christian Hauge, who apparently takes part in organizing a resistance cell. Jens Christian Hauge however was not involved in the resistance movement at this time.

On a sabotage mission, Gregers Gram and Kjartan Sønsteby plant bombs inside an office building while Max Manus guards their bicycles. When the employees start running out, an explosion blows out three windows on the second floor. The middle window is blown out milliseconds after the others, revealing that it's not a real explosion.

The German soldiers play The Badenweiler March while marching down Karl Johans Gate in June 1940. But in the summer of 1939, Germany's Minister of Propaganda Joseph Goebbels signed a police order, forbidding this March to be played except at functions attended by Adolf Hitler, and only in his presence. However, Hitler is not present here, and whoever was responsible would have to pay a fine or go to jail.

When the Germans march down Karl Johan you can see modern buses in the distant background.

A modern, white van can be seen reflected in a store window.