Other mistake: Christina suggests that they have found Atlantis. However, they start in Hawaii, which is in the Pacific. The general consensus is the Atlantis is in the Atlantic (or Mediterranean) and not the Pacific. Some people do suggest that the lost continent of Mu is in the Pacific.
Other mistake: When translating Dutch for English, one translation uses "their" when it should've been "there." It's in the scene when we first see the lead cop talking to his daughter.
Other mistake: When Rico has Walter in the jungle, he yells to Dundee "I know you're up there" (and it echos), then he yells "come down" (and it echos), then he says "or I will shoot your friend", but that line doesn't echo.
Other mistake: When JoJo is babysitting Phoebe, Kat and Tim run in from the rain. His arm had been around her briefly but when she is in the doorway, he is behind her and both his hands hold up a raincoat. JoJo had made up an excuse about Kat's mother being ill to cover for Kat and Tim's absence. Kat and JoJo leave and have a discussion in the car about whether Tim's wife knows about them. JoJo says "So he had his arm around you, so what, right?" But JoJo had not seen his arm around Kat.
Other mistake: Mr. Phillips told Michael (Danny) that he'd like to hear him play on his "Steinway at home", but didn't say when or give Michael his address, but Michael was able to ride his bike to the Phillips' house. Michael was in this new school (and State) for only one day, so it seems unlikely that he'd know where Mr. Phillips lived. (00:26:33)
Other mistake: Ok, this is being nitpicky, but in the scene where Freddy is pretending to be paralysed, and Lawrence (pretending to be a doctor) is whipping him on the legs in front of Janet to taunt him and get him to crack, in reality, Freddy's face would have been bright red from the pain. He could never hide that.
Other mistake: When Angela starts up the chainsaw (to kill Judd with) we hear the sound of it starting but you can see it is not on. (00:35:54)
Other mistake: The 3rd movie takes place 5 years after the original, since Kristen is still in high school this one can't take place too long after that. How does Nancy's house get so run down in only 5 or 6 years?