Factual error: When the teacher announces they are going to Prague, they basically walk around the corner to a waiting bus. This is impossible because the part of Venice they are in is inaccessible to motor vehicles.
Factual error: The German woman screams "Nacht Monkey" when Peter jumps off the train, but the German for "Night Monkey" is "Nachtaffe".
Suggested correction: But his name is "Night Monkey" and would be called that in Germany so she simply confused her German with the English name, perfectly reasonable if she is afraid. Germans call Spider-Man the same as well, not "Spinnemensch."
Factual error: When Peter and Happy fly from the Netherlands to London, they pass the Dorset Coast, which is 150 miles southwest of London and therefore way off the direct route and a huge detour, even though they are supposed to be in a hurry. (01:32:50)