Factual error: At the beginning of the movie, the main characters are supposedly in Amsterdam, but everyone is speaking German, it's not just the main characters doing this.
Factual error: When Paxton arrives at the station at the end of the movie he is supposed to be in Germany, yet there is a sign on the platform which reads 'Praha'. Also watch out for posters and signs in bad german language like an add which reads 'Neu am DVD' (should be 'Neu auf DVD') and a sign with 'Dieser Bahnhof wird Video - bewacht' ('Dieser Bahnhof wird videoüberwacht') on it.
Factual error: In the beginning, the Amsterdam redlight district is shown. They have shown windows on which sex scene shadows appear. Actually, all redlight windows in Amsterdam have big red-colored thick curtains which are closed when any customer gets in with the prostitute. There is no way that shadows can appear and visitors can see it from outside. Doors are also closed from inside, so it is not possible to open it as shown in the film.
Factual error: The amount of blood that comes out of the main characters hand when his fingers are cut off is too much to be realistic at all.
Factual error: When the girl has her eye cut off, pus begins to pour out, but realistically there is no reason for this to happen, nor would it even happen in real life.