When Martin and Rudi rob the gas station and the policeman approaches Martin, the policeman's head is turned right when shown from behind, but turned left when shown from Martin's point of view.
When Henk and Abdul call their boss, you can hear a police siren in the background. That sound is from an American police car, not a German one.
What is called "Helsinki syndrome" in the movie actually is called Stockholm syndrome. The same mistake is also present in Stirb langsam (1988).
When the two leads drive towards the Netherlands, they (and the police cars in pursuit) are photographed by a traffic cam. However, when this happens the camera's flashlight is not used. In reality, the flashlight is always used.
While Rudi sleeps with the whores the foot of the cameraman can be seen.
You can spot a cameraman at the screen bottom in a mass police deployment scene after Rudi and Martin barely make it out of the apothecary.
Microphone is visible at the top of the frame in stairs shootout episode