Revealing mistake: When they are at the Nutmar camp in the mountains, Val Kilmer tells Willow "Get on that shield!" but when they go over a 6, 7, 8 foot drop when they are sledding down the snow, you can clearly see runners on the shield.
Revealing mistake: When the weasels are at Eddie's apartment and Roger is handcuffed to Eddie, Roger runs under the bed and drags Eddie on the floor. As he pulls him you can clearly see a board with wheels under Eddie that is pulling him under the bed. (00:38:50)
Revealing mistake: Adam and Barbara aren't supposed to have reflections, but when they enter the recreation of their home (just before they meet Juno), their reflections are shown perfectly in the glass display case that holds Delia's sculptures, behind them. (00:32:55)
Revealing mistake: Any time when the two girls are in hell's corridors and running around, you see these corridors as stone walls, yet whenever they back up against one of these walls, you can clearly see they are merely rubber sheeting overlayed on a framework as the rubber sheeting bends and contracts very clearly.
Revealing mistake: After her brother's death, there is a scene in which Alice starts practicing with her brother's nun-chuks. They never show the real actress doing the tricks; instead, they cut to an angle from behind her and show a double who has darker, shorter hair than the real actress and is a bit bigger. (00:56:45)
Revealing mistake: A wire can briefly be seen on MAC, as he does the flips in the air, in McDonalds, in the teddy suit. (01:02:55)
Revealing mistake: When Michael and Spike are having a dance off, behind them the road continues. It is so obvious that the road is just a backdrop, along the road the texture and colours change at one particular point, also the sky.
Revealing mistake: None of the grenades Nick throws at the bar does any damage.
Revealing mistake: At the end of the movie when Josh and his friend are walking down the street, a lady crosses the street in front of them. Look closely to the left of the screen. The lady is obviously behind the tree waiting for her cue because she is not seen walking toward the tree before crossing the street. (02:06:40)
Revealing mistake: Near the end, when Eliot enters Frank's office with his rifle, he accidentally shoots into the ceiling. He shoots it at a slight angle, but the rubble falls right on top of his head instead.