Other mistake: Just before the evil robots capture Bill and Ted's girlfriends, after they crash through the window, the girlfriends ask the robots: "Who are you?" and Bill goes "Well, I'm really Evil Ted!" and unzips himself and out pops Evil Ted, and the other robot goes, "And I'm really Evil Bill!" and out pops Evil Bill. When the robots are herding the girlfriends out just before knocking them out with their breath, you can see two sets of clothes in the bottom left corner if you watch closely.
Other mistake: When Gomez begins to flip through his desk calendar, we see that "today" is Thursday, March 28, 1991. He then turns to the date of the "next quarter". The left hand page shows Thursday, August 8, but the right hand page shows Tuesday, September 9. (00:11:15)
Other mistake: When Daniel is at the Italian restaurant with Julia, the waiter says he will bring Daniel 9 pies. When Daniel is carrying them into the hotel after dinner, it is clear is only carrying 8 pies.
Other mistake: In the dance scene, when Mrs. Potts says "true as it can be", in one frame her eyes turn black and then turn blue again. (01:00:25)
Other mistake: Why hasn't there been a mention of Freddy having a child in previous films? Couldn't be because they covered it up, as soon as Freddy was discovered to be the Springwood slasher the media would have been all over him and his family.
Suggested correction: Throughout the entire series, it's shown that there's sort a miniature conspiracy going on where the people of Springwood have been trying to make everyone forget about Kruger, including actively suppressing evidence. It's possible that when he was initially caught, the media was aware of his daughter, but not only would it not have been that big a deal (they were focused on him- not his family) in the decades that have passed since his original "death", the information was likely covered up or ignored in favor of trying to make everyone forget about it. (Hence, even Maggie doesn't know Freddy is her father.) Furthermore, the fact he has a daughter has basically no impact whatsoever on the story thus far, so it makes sense it hasn't been brought up before.
It has never been shown in any nightmare film that there is a cover up conspiracy until Freddy vs Jason (which takes place 5 years after this film), and that cover up begins after the events in this film, evidenced by many characters saying it's been quiet for 5 years.
Other mistake: As Peter stands on top of the rocks, you can see a distinct difference between his appearance and Never-land. Also, as the camera pulls back to follow his progress through the Lost Boys area, a vine is seen shaking on the left side because the camera hit it.
Other mistake: Jack gets hit in the face by a car trunk but when he wakes up later there's no cuts or bruises on him.