Blood Ties - S5-E13
Continuity mistake: When Ben brings him and Dawn some hot chocolate, the cups containing the hot chocolate are in fact two cups, one inside the other, making a total of four separate cups. But once Ben reveals that he is in fact Glory, Dawn's two cups have suddenly changed to just one cup.
I Was Made To Love You - S5-E15
Continuity mistake: At the magic shop, while Giles is talking, he is not wearing his glasses. But right after Spike leaves the magic shop, he is wearing them.
Revealing mistake: After Buffy leaves the cave where Adam kills Forrest, she trips and falls down a horizontal slope. She then rolls over some rocks and one of the rocks wobbles.
Where The Wild Things Are - S4-E18
Visible crew/equipment: After Anya has rescued Xander from drowning, they venture through the vines to the room that Buffy and Riley are in. The moment before Anya screams, "Xander, help me," a vine attacks her, but a crew member's hand can be seen (in the wide-screen version) moving the vine towards Anya.
Once More, With Feeling - S6-E7
Visible crew/equipment: Right after the "I'll never tell" song, Giles, Anya and Xander walk down the sidewalk, the cameraman is visible for a short time in the windows on their left. (00:17:05)
The Harsh Light Of Day - S4-E3
Continuity mistake: When Spike and Harmony find the treasure room containing the Jewel or Ring of Amarah, after Spike stakes Harmony he removes the necklace he had on, but in the next shot he's wearing the necklace again.
All The Way - S6-E6
Continuity mistake: After Spike has fought with the vampire claiming to be a rebel and he is re-loading his cross bow, he is tackled by another vampire and you can hear the sound of the cross bow firing, but as he falls you can see the arrow is still loaded.
Plot hole: Spike must have had his chip implanted while he was unconcious. If so, how did he attack The Initiative scientists without any pain when he tried to escape? You could argue that they programmed him to be capable of violence within The Initiative only, but why would super smart scientists program an evil being to be able to escape at the first opportunity? Joss Whedon has acknowledged this as an oversight.
Continuity mistake: After the group find out Jonathon cast a spell, Willow is holding a book to her chest. But in the side shot, the book is resting on her stomach and then back on her chest a few shots later.
Continuity mistake: Willow's hair changes position between shots when the vampire brushes her hair back and kisses her.
Visible crew/equipment: Near the start, just after Buffy kicks the vampire onto the roundabout, check the top left corner of the screen as she says her line - boom in shot. (00:02:35)
Continuity mistake: When Veruca comes to Oz's cage to spend the night there, she tosses her jacket onto the round stone thingie (knob?) at the end of the stairs, and it covers the whole thing. However, when Willow discovers them in the morning and Veruca goes to pick up her jacket, you can see that it has moved. Willow didn't touch it when she entered, and both Oz and Veruca were locked up so they couldn't get anywhere near it. (00:26:35 - 00:29:20)
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)
Continuity mistake: In the season two episode, 'When She Was Bad', in the scene where Buffy smashes the masters skeleton with a sledge-hammer she smashes the rib cage to pieces. Suddenly the rib cage has again become completely intact and she smashes it to hell again. (00:40:35)
The Dark Age - S2-E8
Revealing mistake: When Buffy and Giles are talking in the school in the final scene, the same extra (in a beige shirt and blue jeans) walks out of the room behind Buffy twice. (00:42:50)
School Hard - S2-E3
Continuity mistake: When Cordelia comes up to Buffy talking about how "even slaves get minimum wage", in pretty much every shot her arms switch from being at her sides to crossed in front of her, held behind her or on her hips.
Audio problem: When Jenny and Giles are talking and Jenny is talking about the festival, they walk behind a drinks machine and then her lips don't match up with what she says.
Answer: She has superpowers, ergo fast movement. The reason she outruns him so easily in "Touched" is that she stops trying to actually fight him and just dodges instead.
Shay