Miscellaneous: Mick yells at the buffalo; "Out of the way, dopey!", so it's clearly in the way. When he pacifies the buffalo, it lies down in the middle of the road, so he hasn't actually made it any easier to get by it. Incidentally, the next scene doesn't show how they get the truck past the buffalo.
Audio/visual unsynchronized: In the scene where Mick is talking to the prostitutes, the pimp asks Mick if he is going to "screw" one of them. During the sentence, his mouth clearly forms the F-word, but it has been dubbed over.
Errors in geography: Mick enters the subway at the 59th Street-Columbus Circle station at the end of the film, but the wall tiles feature the number 9, since the scene was filmed at the 9th Avenue station on the BMT Culver Line.
Crew or equipment visible: In the subway scene, right after Crocodile Dundee climbs up to walk over the crowd in the subway station, if you look at his feet you can briefly see the platform used to assist him in walking.
Errors made by characters (possibly deliberate errors by the filmmakers): The phrase Richard says in Italian to the waiter in the Italian restaurant doesn't make any sense. The first two words, "e' stato" means "he was". The next word is a non-existent conjugation of the verb "piacere". The last word, "rivedertu", while it was technically said correctly, should have been preceded by the word "di" since there are three verbs in a row. Based on the action, he may have been saying something to the effect of "he was pleased to check you."