Shay

The Killer In Me - S7-E13

Continuity mistake: Spike tells Buffy about drugs The Initiative would give him when his chip started firing after he was first captured. This is wrong in two ways: firstly, we saw most of Spike's time in captivity, and he escaped before they could drug him, and secondly, he didn't even know he had a chip until he escaped and tried to kill Willow.

Shay

Angel - S1-E7

Continuity mistake: When Buffy leaves the Bronze (right before the Three attack her) to go home, she passes a strange-looking green-lit window. After the attack, she and Angel run past this window again, even though they're heading in the same direction Buffy was going anyway.

Shay

Wrecked - S6-E10

Continuity mistake: The episode begins the morning after Buffy and Spike first have sex. That night, Willow and Amy go out again to find Rack's place, and this cuts directly to Willow waking up the next morning. But later in the episode, Spike makes repeated references to what happened between him and Buffy "last night", when in fact it was two nights ago.

Shay

Once More, With Feeling - S6-E7

Revealing mistake: During the song-and-dance number "They Got The Mustard Out", if you look closely at the dancers, the man in green to camera right of the second row is horribly out of step with the music, and with the rest of the group. The spell makes everyone dance far better than they naturally would (Tara loses the clumsiness she often displays, for example), so it is a mistake to have someone under the spell dancing so badly.

Shay

Hush - S4-E10

Continuity mistake: The first night that the Gentlemen float through the college, they are on the 2nd floor one minute (all the room numbers start with 2), then they turn a corner and are suddenly outside room 118, a floor below.

Shay

Hush - S4-E10

Revealing mistake: In the fight scene at the clock tower, the first time Riley is knocked to the ground he kicks one of the strait-jacket demons in the face - his foot misses, but the demon still reacts as if hit.

Shay

Innocence (2) - S2-E14

Continuity mistake: When Buffy is told that Angel has become Angelus, she mentions "I should have known. When I saw him at the house he was different", but her earlier conversation with him took place not at the house but at his apartment. This isn't just a strange turn of phrase - the scene was originally shot at the Summers house, but was changed to Angel's apartment for more emotional resonance.

Shay

Earshot - S3-E18

Continuity mistake: When Buffy is trying to read Angel's mind, his chain goes from being inside to outside his vest between shots.

Shay

Passion - S2-E17

Deliberate mistake: After Jenny pushes the janitor's cart into Angelus and runs up the stairs, there's no physical way he could be waiting for her at the top of the stairs (even with vampiric speed). Joss Whedon has admitted in interviews that he put in this blatant continuity error as the situation is a staple of the horror genre (girl runs from villain, only to find him standing right in front of her).

Shay

School Hard - S2-E3

Plot hole: When Buffy and Sheila are walking out of school after the meeting with Snyder, Xander runs up to talk to them. He mentions during this scene how Buffy will be helping out at the Parent-Teacher Night, but he shouldn't know this - Buffy only just found out about it in the meeting with Snyder.

Shay

School Hard - S2-E3

Revealing mistake: When Spike is talking to the Anointed One for the first time, one of the henchmen tries to rush him from behind and Spike backhands him without even looking, but Spike's hand movements, the reaction of the henchman and the sound of the punch connecting on the audio track are all out of sync.

Shay

The Wish - S3-E9

Continuity mistake: Anyanka's demon face in "The Wish" is very different to her demon face any of the other times we see her ("Entropy", "Selfless" etc).

Shay

Get It Done - S7-E15

Plot hole: When Dawn and Buffy discover Chloe hanging in the bathroom, Dawn gives a little gasp but nothing more. But, seconds later, some Potentials run from across the hall saying "What is it? We heard -" before they see Chloe. While it suits the next scene to have them there, there wouldn't have been any sounds loud enough for them to have heard from across the hall through a closed door.

Shay

Consequences - S3-E15

Other mistake: When the detective is interviewing the woman in the alley he says "So you heard the man scream about what time?", but Finch didn't scream as he died.

Shay

Enemies - S3-E17

Revealing mistake: Watch Xander's right leg as Angelus punches him onto the sidewalk - it bends the wrong way at the knee and flies up to his waist, showing that it's a dummy.

Shay

Enemies - S3-E17

Revealing mistake: After Faith brings Angelus back, when she goes to punch him and he blocks, the stuntman switch is very obvious - he's noticeably taller, has different hair and doesn't even seem to be wearing any vampire make-up.

Shay

Consequences - S3-E15

Continuity mistake: When the detective is interviewing the woman in the alley, he mentions that the murder took place "last night". In "Bad Girls", we see Buffy visiting Faith the day after the murder, and that night is presumably when she has the dream about drowning, so by the time the detective is asking this question it is actually two nights after the murder, not one.

Shay

The Zeppo - S3-E13

Continuity mistake: In the basement scene, when Jack and Xander face off over the ticking bomb, the number of beeps is hugely disproportionate to the seconds ticking down.

Shay

Beauty And The Beasts - S3-E4

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.

Shay

Halloween - S2-E6

Other mistake: When Buffy and Willow find the picture of the noblewoman in the Watcher's Diaries, Buffy asks "Who is she?" and Willow replies "It doesn't say", but if you watch closely you can see that during the brief shot of the book her name is visible next to her picture.

Shay