Continuity mistake: In the scene where the Asian gang is ramming Porter with their car, when they hit him the windshield gets smashed. When they all get back in their car and drive off the windshield is fine. (00:47:15 - 00:48:35)
Revealing mistake: In the David Letterman scenes, Paul Schaeffer's head is shaved, which he just did recently (maybe within the last year to year and a half). (01:15:00)
Continuity mistake: When Kelly is on the boat with Hank and the soon to be headless deputy, her green vest (life-jacket) is fully unzipped. When we see her immediately after she's been knocked in the water, her jacket is zipped almost all the way up.
Continuity mistake: Near the end of the movie when the 'false' Buzz Light Year is running along the air conditioning ducts his 'New Utility Belt' disappears then reappears again. (01:01:55)
Continuity mistake: In the whipped cream bikini scene, when Mox pulls back from kissing the cheerleader he has whipped cream on his shirt. In the next shot it's not there.
Visible crew/equipment: When Jim West is hanging by the rains of the horse you can see the rider's boot as Jim West is telling the horses to back up.
Continuity mistake: When Lance arrives at the church to call off the wedding, he exits an old model cab with a square body. As he's walking up the church stairs the cab pulls off and is a newer model.
Continuity mistake: When Hawk is drinking the Bourbon on the rocks, the lemon wedge disappears when he spits out, and re-appears after the scene when the lady giggles.
Continuity mistake: In the scene where the pet shop girl reaches into the aquarium, clearly the whole chest part of her shirt is submerged in the water. When it cuts to her at the counter only the area around her nipples is wet.
Continuity mistake: When he is playing Tetris, he is playing a different game every time. (00:43:35)
Continuity mistake: When Silent Bob renders the demon disabled by using the anti-odour spray, you see him take the spray out of his coat and spray with his thumb. However, it cuts to a front view, and he is clearly seen using his index finger. It then cuts to Bob's rear, and he is, again, spraying with his thumb.
Continuity mistake: The first time Matthew Perry's in Neve Campbell's apartment before he realises she thinks he's gay, he fills two glasses of wine in two very different glasses. He hands one to her and holds the other himself, in the next shot they hold different glasses, then again in the third.
Continuity mistake: When Tracy sets up her card table before school there's a close up of each leg being flipped out. If you count; theres five legs shown from a four legged table.
Continuity mistake: When Craig first discovers the portal door his crouching position changes slightly between the camera shot inside the tunnel and that from the office, and again when he closes the office door and goes back to the portal door.
Continuity mistake: When Sikes is put into the headpiece and Claw has the power turned up full force the chin strap is first around Sikes's chin, then it isn't, then it is.
Other mistake: When the sex scene with Robert De Niro and his lover is over, you can see that he is wearing underwear.
Visible crew/equipment: A boom mike drops into frame during Jay Mohr and Scott Wolf's dialogue at the supermarket.
Continuity mistake: When Mary's grandma is teaching her to dance, Mary falls and breaks the table, but later when it flashes back the table is fixed then it's broken again.
Continuity mistake: In the shoe shop Carla's blouse changes from pink to beige. (00:12:40)
Continuity mistake: At the end of the movie, when the Mystery team are consoling each other at the end of the game, the keeper is in the net, after he had been pulled and then stayed off when Mystery tried to score the equaliser.