Continuity mistake: In episode 'Anne', when fighting the hell dimension demons Buffy's shoes change from trainers to plain pumps in different shots.
Revealing mistake: When Buffy saves the man from being hit by a car, there is a very quick shot of the man standing in front of the car. In this shot, Buffy can seen on the left hand side of the screen running into the street to save him. But the shot then immediately cuts to Buffy who is suddenly still standing on the other side of the street with Lily and runs into the street to save him again.
Continuity mistake: When Buffy fights the guards and says, "Anyone who isn't having any fun here follow me," the top under her jacket is purple. In the next shot, when she turns to walk out, it is green, then back to purple when we see her again.
Visible crew/equipment: Near the end after freeing the prisoners, Buffy fends off Ken's henchmen on a raised platform. At some point during the fight she is grabbed by one of the henchmen and punched in the stomach by two others. She then breaks free and throws one of them off the raised platform - onto a large crash mat. Please note that this is a separate mistake to the one already submitted as it is talking about a different crash mat.
Audio problem: The drummer in Oz's band's movements don't match the song that is heard when we first see them performing at Buffy's house.
Continuity mistake: When Buffy decides to leave again and goes to her room to pack, her door is three quarters shut when she goes in, half open when Willow comes in and almost fully open when Joyce comes in. At no point does anybody touch this door.
Character mistake: When the zombies break into Buffy's house, she stakes one to check if it's a vampire. But she should know full well that it isn't a vampire as they all broke into her house without being invited.
Continuity mistake: When Pat puts on the demon mask and punches Buffy into the bedroom door, she hits the door with her back and then falls to the floor on her face. In the immediate shot she hits the floor again, but this time on her back.
Continuity mistake: When Joyce throws the bag with the stray cat into it into the hole, the bag lands with the knot at the top right, and shows no signs of moving. They chat for a few seconds about something to say, then when Buffy starts filling in the hole (with no sound of a moving bag), the bag's now lying with the knot on the left.
Continuity mistake: After Buffy is supposed to meet Willow and she is walking home you can see she is wearing light blue wedge heels but when she is down in the basement she is wearing completely different purple heels.
Revealing mistake: During Faith's fight outside the Bronze in 'Faith, Hope And Trick' when she stakes the vampire, if you watch carefully, you can see the rubber stake bending. (00:15:20)
Other mistake: When Angel fights with Buffy in the forest you can see that he hasn't got shoes on, just socks. Later, when Buffy goes back to the mansion and Angel is chained up, he's wearing shoes. How did he manage to put them on, if he was in chains?
Continuity mistake: When Buffy is in the counsellor's office she is wearing a yellow kind of gauzey cardigan which alternates between being completely buttoned up to unbuttoned between shots.
Revealing mistake: In the teaser of "Beauty And The Beasts", when Jeff is running through the woods, you can see in the top left corner of several shots a lamp being used to light the scene.
Homecoming - S3-E5
Continuity mistake: In numerous episodes, including 'Homecoming', we see vampires being killed when they weren't stabbed through the heart (the Texan girl vampire in this episode is stabbed practically in the stomach). But the show also makes an issue of the fact you have to stab a vampire directly in the heart to kill it (think the flashback in 'the Becoming, Part 2' where Buffy misses the vampire's heart, or 'Pangs' where Spike gets staked several times).
Homecoming - S3-E5
Visible crew/equipment: When Buffy and Faith are in the library, a person's arm wearing a white shirt can be seen on the left side of the screen behind Buffy in one shot.
Band Candy - S3-E6
Continuity mistake: The tattoo on Giles' arm is reversed compared to the way it was facing in the "Dark Age" in season 2.
Revelations - S3-E7
Revealing mistake: When Gwendolyn Post fights Angel in the mansion, she breaks a long-handled shovel over her knee to create a stake. If you watch in slow motion, the handle of the shovel is pre-broken (she simply holds the two pieces together tightly), and the pieces separate just before they actually make contact with her knee. (00:34:55)
Chosen answer: He had larangitis and because of the shooting specifications they had to have him shoot the scene with a bad throat, they then re-recorded his lines and dubbed them. At various points during the scene and indeed the episode you can see him touch his throat or rub it.