Other mistake: Rattner and DiMone are game planning about Rattner's date with Stacy (Leigh). DiMone tells Rattner that all he needs to do to score with Stacy is play songs from side 1 of "Led Zeppelin IV" (Zoso). You then hear the song "Kashmere", which is on the album "Physical Graffiti".
Suggested correction: Damone (not DiMone), told Rat that when they were making out to put on side 1 of Led Zeppelin IV. The fact that Rat is playing Kashmir from Physical Graffiti is just to show that Rat was unclear about Damone's instructions.
Not sure if Rat is unclear about Damone's instructions... he said he had 4 steps to making sure that getting a date with Stacy and keeping her around, and if all else fails, to play side one of LZ-IV... seems that Rat would (should) have asked if he was unclear then at that point considering Rat had a crush on her throughout the movie. I think that it's more of a musical inside joke if anyone was/is familiar with the Zep catalog realizing two things - one, the first four steps of Damone's plan didn't work being that his character was pretty shady and fake (off camera...because you don't see Rat implementing any of them) and two, that "he can't even get the music correct" due to his nervousness.
Other mistake: Sam draws an orange vest for Lockwood using a dark crayon. (01:10:45)
Other mistake: When Marty returns to 1985 from 1885 the time machine is destroyed by a train. What is strange is that not only does the train not stop (which is mandatory in the event of an accident) but there is also no reaction from people nearby, such as those in the vehicles waiting to cross the track at the level crossing. Later, when Marty returns to the site with Jennifer, there is still no sign of police officers or other officials.
Other mistake: At the very beginning of the movie, when the guy throws the match into the house, it doesn't enter through the window. The match crashes and bounces back, but the fire inside the house still occurs. (00:02:40)
Other mistake: When Hamm turns off the TV at the beginning, there's no reflection of him, Rex who is beside him, or the remote. (00:06:58)
Other mistake: When the three ninjas are kidnapped and locked in that room, Tum-Tum is complaining about being hungry. Later on, before the fighting match between Grandpa and Snider, Tum-Tum gives Grandpa jelly beans. Why didn't Tum-Tum just eat those before?
Other mistake: When Marcus and Kevin reveal their real identities to the crowd, their eye colour changes from blue to brown without any indication that they removed their contact lenses. They simply lift off their masks. (01:38:10)
Other mistake: Towards the end when we see one of the $100 bill plates up close, the plate is not of any money ever put into production in the US. While I know most movies do not try and use actual money, there are things that don't match how real money is made: serial numbers are not on the plates, circle around Ben's head doesn't go to the border, "The United States of America" is missing above the "100" on the left, just to name a few.
Other mistake: In the credits, Kareem Abdul-Jabbar's name is misspelled Kareem Abdul-Jabaar. (01:23:40)
Other mistake: When Leela is signing the petition, Amy grows a third arm for a split second.
Other mistake: As Dark Helmet says his line "Everybody knows that!", watch the crewman in white to Helmet's right. He starts to cover his crotch a beat too soon.
Other mistake: In scene where Celeste follows her niece Lori to Jeffrey's Apt, she is trying to fool the Doorman and says "He's in 11-A, right?" He replies "2D." Later, when Jeffrey catches Celeste on the fir escape and let's her out via his front door, the apt door is marked "2A."
Other mistake: Catherine lives in apartment 1 on the first floor, but she goes in to apartment 4 on the second floor and right in front of Neil's apartment. (00:06:26 - 01:10:28)
Other mistake: Jon's Volvo back license plate number in the first half of the movie is T03-851. When he and Dr Liz are looking for Odie, his front license plate number is I35-749. As they are pulling up to the train station, the Volvo in front of them also has the plate I35-749.
Other mistake: When Franc (Martin Short) is looking at the house to see the changes for the wedding and they are talking about the menu, Kimberly Williams starts with her hair in a ponytail, then for a split second her hair is half up in a barrette and then it's back to a pony tail (or vice versa).
Other mistake: When Skinner calls his lawyer he never dials the phone.
Other mistake: When Westley and Buttercup are in the fire swamp and Buttercup is burned for the first time look carefully at the fire spurt, it's several feet away from Buttercup and is clearly too far away to have burned her.
Other mistake: When Margaret and Andrew first walk into the Immigration Office there are a group of extras seated directly to the left of them, in two rows. One of them, a guy with glasses and long black hair, wearing a white shirt with patterns (back row, second from the wall, next to the guy in the light yellow shirt), briefly looks at the camera as Margaret and Andrew walk by.
Other mistake: When Stallone stops the bad guys in the semi full of cocaine, they fly through a windshield that is apparently made of plate glass, and not the safety glass found on almost every other vehicle windshield on earth.
Other mistake: In the scene where Paolo leaves the stage after everyone discovers that he can't sing, his bodyguard Serge stops him and Paolo suddenly loses his Italian accent. Paolo sounds very American when he says "You work for me, Serge."