When Crucial Taunt are playing in Cassandra's apartment as Wayne and Garth head to Milwaukee, there is no echo on the audio. However, when the band stop playing, there is a very clear echo when Cassandra and Benjamin talk and even on the rustling of the papers in her hands so there would certainly be a noticeable echo when the band played.
Noah Vanderhoff is talking to Benjamin Kane, explaining the commercials for his chain of stores, Noah's Arcade. He says, "I do my own commercials. Course, I don't mention the games in the commercials, 'cause the technology moves so much faster than the advertising." Yet in the beginning of the movie, they show Benjamin watching a Noah's Arcade commercial, where Vanderhoff is seen specifically listing the video games in his arcades, games like "Zandar, Beauwolf, Ninja Commando, SnakeAZon, Psycho Chopper..."
A crew member (named Terry) gives Wayne and Garth a countdown in the new TV studio. While the words "two" and "one" are normally omitted, Terry says "two" on the third take. He acknowledges his mistake by chuckling briefly before Wayne and Garth begin their show.
At the start of the "gratuitous sex scene", Wayne is alternating opening and closing his eyes, saying "Camera 1" and "Camera 2". When he starts, "Camera 1" is closer to Cassandra's left than "Camera 2", meaning that Camera 1 is Wayne's right eye, and Camera 2 is his left eye. At the end of that part of the scene, however, he says "Camera 2" last, but his right eye is open, which should be Camera 1 if he had been consistent.
The show Benjamin watches at the beginning of the movie and the tape (of the same episode) that he shows Van Der Hoff, are different. The second time it is seen, Wayne pauses and stutters on words he didn't the first time.
In the donut shop, in the scene where Wayne and Garth make up, look closely at the straws Garth has stabbed into his donut figurines - one of them changes from red to blue between shots (the director acknowledges this in the DVD commentary.)
Wayne starts playing the Stratocaster in the music store and the clerk points to a sign that says "NO STAIRWAY TO HEAVEN." But he's clearly playing a different song entirely (original theatrical cuts actually used Stairway, but this was changed for home video releases for legal reasons, and as a result the joke no longer makes sense.)
When Cassandra comes off stage after Crucial Taunts set at Gasworks. Two guys have a fight and spill beer over her, she get mad and does a kung-fu style kick at one of them. Her right suspender belt becomes undone, yet when she sighs and walks over to the bar, its still done up.
When Wayne gets pulled over by the cop, the cop is seen (in the mirror) removing his glasses and helmet. When he shows Wayne the picture, the glasses disappear from his left hand. But in the far-away shot when Wayne is zooming away, the glasses are back in his left hand and the picture disappeared.
After Garth shocks the guy in the gasworks he juggles his weapon to impress some babes. Just before that cut there is a babe in pink to Garth's left. During the cut there is a babe in black to Garth's left, occupying the same spot. After the cut, the babe in pink is back.
While Wayne is talking to Cassandra at the bar in Gasworks, the bartender in the background is always positioned behind whoever is speaking as the camera cuts back and fourth between the two during their conversation.
When Wayne and Garth go to the Gasworks, Garth is picked up and
thrown by the big guy. He then goes and puts on his electric zapper belt, which is put on over his shirt. When he is back inside the Gasworks, the belt is under his shirt, which he then moves to reveal it.
When Garth's dog comes into his bedroom to tell him Wayne is waiting outside, she walks towards the bed and stops with her foot on an item of black clothing. In the next shot, you are looking at her from the front and there is clear floor in front of her.
Frankie Sharp's Vanity plate "MR BIGGG" has no Statue of Liberty on it when it is shown in Milwaukee, but yet when we see it in Chicago during the Mission Impossible theme montage it has the Statue of Liberty to the right on the plate.
When Wayne opens up the camera at Cassandra's video shoot, the film spills out straight on the ground. But in the next shot, the film is spitting out at an angle. And when Wayne and Cassandra drive away, there iss no film coming out of the camera or on the ground.
In the music store scene, Garth can be seen walking towards, then standing in front of the drums in the background. After taking his seat behind the drums, the camera cuts back to Wayne showing Garth again in front of the drums just before his drum solo.
When Garth first sits down behind the drum set in the music store, there is a sunburst Les Paul guitar hanging on the wall behind his head. When he starts playing the drums and lights change, the guitar is no longer there.
'Rob Lowe (I)''s character is listed as "Benjamin Oliver"
in the credits, but when he first meets Wayne and Garth, he introduces himself as "Benjamin Cain." Contrary to popular belief, this isn't a goof, but a deliberate joke by the crew - a crew member's child had a friend named Oliver Benjamin.