Continuity mistake: The morning after the party at Chip's, and Chip is at Steven's house making eggs for them, watch closely as Chip eats. While they are talking about Heather being a prostitute, Chip repeatedly loses the eggs off of his fork, but continues to put the fork in his mouth, and makes a sound like he is actually eating the eggs. He does it about 4 or 5 times during their whole conversation.
Continuity mistake: During the "Midnight Express" scene, Chip opens his shirt and presses his chest against the glass. The shot moves to Steven, and as we pan back to Chip, he is sitting, phone in hand, with his shirt buttoned.
Continuity mistake: In the scene when the two guys (Steven and Ernie Douglas - the cable man) are sitting in the cable TV van, when Steven first asks about the cable guy's name, in the first shot we can see Ernie saying his name. In the next shot, he's making a strange smile and then the last shot shows a similar view to the first shot. It is clear that the first and the last shots were one complete and the smile in the middle was added later. There are two different head positions for Jim Carrey.
Continuity mistake: In the scene at Steven's parents house as Steven is yelling at Chip for being a felon, Chip gets up and slowly walks right next to Steven and whispers something in his hear, Steven instantly is moved back one or two feet in the next camera shot before he had a chance to move and he punches Chip in the mouth.
Continuity mistake: In the scene where Chip and Steven are jousting at Medieval Times, Steven knocks Chip of his horse, and Chip drops his lance right before he goes flying back a large number of feet. In the next shot, the lance is behind Chip.
Continuity mistake: During the Medieval fight scene, Chip hits Steven's helmet and the first shot shows Steven's helmet turned. In a following shot the helmet is on normally, then Steven is shown turning the helmet right again.
Continuity mistake: There are numerous instances in the film where Jim Carrey forgets that his character has a lisp. The most obvious example is when Chip goes to Robin's apartment to install free cable. In order to get Robin's attention he says "Apparently you have a secret admirer" absolutely flawlessly.
Other mistake: In the scene where Chip breaks the glass on the backboard, he falls on his back in the glass. If you look, there is a perfect outline of his body in the glass where he is supposed to land.
Audio problem: In the, "Midnight Express" Scene where Chip is talking to Steven on the phone, at one point Steven yells at the guards to arrest Chip because he was the one that framed him, after this Chip talks says on the phone quietly, "Hey Bernie, Hows that Sports Package" And Bernie gives him a thumbs up. Bernie was standing in the back of the room, without the phone and considering how quietly Chip said it there was no way that Bernie could have heard it.
Continuity mistake: At Stevens parents house, Steven tells Chip Douglas to stay out of his life. Chip says, maybe I should just go, just then Robin stands up on Chip Douglas' right side and takes two steps in front of him and tells Steven he's an @-hole. The camera cuts to Steven and he says "what". Then when the camera cuts back, Robin is way behind Chip Douglas to his left.
Continuity mistake: Watch Chip's weapon change in his hands from the shot when he sweeps Stephen's ankle to the birds eye view, the position and direction of the weapon changes.
Continuity mistake: At the end of the basketball scene, the camera is behind Chip and he is talking to Steven. He is standing in the center of the shattered glass from the backboard. When Steven walks away, the angle changes and shows Chip standing with all of the glass behind him, even though he hasn't taken any steps.
Continuity mistake: When the cable guy (Jim Carrey) gets done drilling in the wall he says, "Suit yourself, no sweat off my sack." and Steven (Mathew Broderick) is seen in the background walking completely through the doorway. However, when the cable guy turns around and says, "By the way, you might wanna put on a bathing suit..." Steven is not even at the doorway yet.
Continuity mistake: At the party when Chip takes the photos, when he takes the one of Steve's friend, the photo slides right out, like in a normal Polaroid camera, but when he takes the photos of Steve and the girl, he takes two in a row and neither come out.
Continuity mistake: When Chip's talking to Steven through the glass, after he stops talking about the Midnight Express, you can see he has no phone in his hand yet when Steven's telling the guard to arrest him he has the phone in it.
Other mistake: In the bathroom scene Chip throws Robin's date into the hand dryer, but you can see he doesn't hit the dryer.