Continuity mistake: In the scene when Spike was in Buffy's kitchen with Joyce, Buffy keeps him down on the table and grips Spike by the throat. She uses her left hand (in the close shot it is also the left hand) but in the next scene when Angel is also in the kitchen and Spike hits Buffy's hand, she uses her right hand (Spike hits her right hand).
Continuity mistake: In Innocence, when the Scoobies are in the library, Oz (I think) says for the crew to meet outside Xander's house a half hour later. Then we cut to Buffy strolling through Sunnydale High in broad daylight, then back to Oz's van outside the military base and it's last night again. (00:23:15 - 00:29:20)
Continuity mistake: In the scene where Buffy and Kathy are deliberately infuriating each other (tapping pencils and cracking eggs) there are several lights on throughout the room (on Buffy's desk, above Kathy's computer, in the kitchenette) yet when Buffy turns out her bedside lamp, the entire area is thrown into darkness.
Continuity mistake: In 'Tabula Rasa' when the loan shark's henchmen throw a stake at Spike at the start it flies over his head and hits a tree. But, if you compare the angle they approach from with the relative positions of Spike and the tree you can see it would have had to do a 90 degree turn in mid air to fly over his head before hitting the tree. (00:01:00)
Continuity mistake: Near the beginning when Buffy and Willow are talking about Willow getting together with Oz, Buffy's hair is in front of her ears. Then she turns to face Willow to say, "You think he's too old 'cause he's a senior? My boyfriend had a bicentennial," and in that shot change, her hair switches to behind her ear then goes back to being in front of her ears in the next shot without her every touching her hair.
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: In Bargaining, part 1, Anya is talking to Giles while he trains the Buffybot. There's a shot from behind and we can the corner of her jumper move around as she turns away, then it cuts back to a front view of her and she's still facing Giles. (00:26:20)
Continuity mistake: Shortly after the opening credits we see Buffy, Dawn and Xander driving to the new high school. As they're talking, the rest of the credits roll by onscreen. Just after "Producer: Marc David Alpert" is shown, there is a side-angle shot of the car and you can see Xander's left arm resting outside on the open door window. But in the following shot he has both his hands on the steering wheel.
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.