Deliberate mistake: In the towel-dance scene after Demi has put on her white panties and spins off the towel from her hair she starts to rip off her body towel. Then in the next frame the towel is again tucked in. Apparently they didn't want Demi topless when she leaned over to slip on her blue shorts.
Deliberate mistake: When the Trunchbull is drinking from the glass with the newt in it, you can easily see that she doesn't actually drink anything, as the water level stays exactly the same. Logical, as the newt is real, but it's still very obvious because she drinks for about 15 seconds. (00:46:55)
Deliberate mistake: When the Looney Tunes are playing basketball against the aliens, if you look in the stands the same cartoon characters are in different places at the same time. This happens a lot.
Deliberate mistake: At the end just before the president is killed he fixes his tie, but it keeps on getting fixed to messed, to fixed, etc. Deliberate homage to "A Few Good Men", but worth looking for nonetheless. (00:28:15)
Deliberate mistake: Practically all movies incorporate the name of the movie within the dialog. However, they must remember the English language and tense agreement. On at least two occasions, Fishburne says "Come on Dodge, lets FLED." If they were so interested in incorporating the name within the script, they should have named the movie FLEE.
Deliberate mistake: In the beginning of the movie when Happy first discovers his swing, the balls that hit the people down the street are never visible upon impact.
Deliberate mistake: At the beginning of the movie, Ashtray gets his hair lined up saying, "Kick Me". However, in the rest of the movie, like the scene where he hugs his grandma, it shows the back of his head and there is no words.
Deliberate mistake: The Bradys are shown flying to Hawaii on a small DC-9, but the cabin interior is that of a much larger airliner (most likely a 747). (01:07:40 - 01:08:53)
Deliberate mistake: In the scene where Joan and the kids pile into the station wagon after Stanley is kidnapped, Joan tells the kids to hold on tight and puts the car into reverse. However, in the matter of seconds that have gone by, Joan hasn't even started the car, yet she was able to put it in reverse and drive off. Even if she had the skills to start it that fast, you would hear the car turn over. The car is never heard turning on.