Revealing mistake: In the scene where the kids are shooting arrows and the coach gets hit by one, they send a girl to call 911. If you look closely and follow her in the background, after she runs a few yards, she slows down and eventually stops and stands there playing with her hair. Talk about help...
Continuity mistake: When Kat and Patrick are playing paintball right before they kiss you can see that they are barely covered in paint. When they do kiss and are on the ground, they are totally covered with it.
Audio problem: When Patrick starts singing and gets that marching band to play, look closely at the cymbal player when he bangs them together - it makes the sound, but they don't touch.
Revealing mistake: In the scene where Joey parks his car behind Kat's you hear him coming up really fast and then you see it stop, but if you look in the window across the street you can see in the reflection that the car was still and then it just moves up a little bit.
Continuity mistake: In the scene after Joey draws the penis on the guy's face, the penis drawing gets darker and more defined between when Joey initially drew it and the next.
Continuity mistake: When Joey stops his convertible at the back of Kat's car, it's parked with his left fender right behind the other car's back bumper. But when Kat reverses, it's a few feet further forward so she hits the left door.
Revealing mistake: In the scene where Michael is speaking to Cameron after being insulted by Kat, he drives over the edge of the pavement on his bike. If you look carefully at the pavement as he drives over the edge, you are able to see a ramp that is aiding him in driving over.
Continuity mistake: When Bianca takes Cameron to Kat's room, she opens the third drawer. But when the camera angle changes, it's the second drawer that's opened.
Continuity mistake: When Cameron's friend is putting on his helmet before he goes on the motorbike you can clearly see the goggles strap over the helmet. He gets on his bike and is run off the cliff but after he gets up the strap is nowhere to be seen but his goggles are still on.
Audio problem: When Patrick is going to sing to Kat, using the speaker system during football practice, there's feedback from the microphone BEFORE he raises the faders on the mixer.
Continuity mistake: During the prom scene Save Ferris is playing 'I Know'; it switches from the middle back to the beginning and then the end of the song over the course of the scene.
Continuity mistake: After Pat serenades Kat on the field, you see a shot of a "Detention Sign-In" board, where there are 9 names written, including that of Patrick Verona. However, inside the class, there are at least 14 people, all who are visible when Kat walks through the door.
Continuity mistake: In the second scene where Cameron and Michael are talking to Pat in the shop, Pat puts down a bunch of triangles onto a glass surface. When the camera changes shots, he suddenly has more triangles in his hand, and he puts them down again.
Revealing mistake: The Pedalo is not moving forward, even though Kat and Patrick are cycling away. Also, the two people are supposed to cycle at the same rate - Kat and Patrick are not.
Continuity mistake: When Michael is on his scooter, his goggles are up on his helmet, but a split second later when he pulls up to Cameron, the goggles are on his face. It's all one continuous sequence and he's in shot the whole time - there's no chance for him to pull them down without us seeing.
Continuity mistake: In the scene where Kat rams Joey's car her hands continuously change position on the steering wheel without Kat actually moving. First she's reaching under it, then in a closeup she puts her hand on it from above, then in the original angle her hand's underneath again.
Revealing mistake: When the totally drunk Kat and Patrick are outside the party on the swings, Kat throws up. The characteristic sound of vomit hitting the ground can be heard but it's pretty obvious even though her hair hides part of it that nothing comes out of her mouth.
Continuity mistake: When Kat and Patrick are in the car after the party, when they're driving there's no rear view mirror, but one appears once they stop.