Continuity mistake: When Buffy goes to find Giles, who is going through newspapers, she asks him if he's found anything and he says "I don't know." Between shots Buffy goes from looking at him to glancing downwards with her eyes and then looking back up again between cuts.
Continuity mistake: When Buffy goes to take her history test near the beginning of the episode and is talking to Cordelia outside the door about how she doesn't think she can pass, pay attention. As it cuts back and forth from Buffy to Cordelia, you see the same student (an African American girl with a black jacket, white shirt and earrings) enter the history classroom twice.
Continuity mistake: At the beginning, when Joyce drops off Buffy at school, pay attention to the car windows. They open and close repeatedly throughout the scene depending on the angle. (This seems to be for the benefit of the scene depending on the camera angle. They seem to lower the window the camera is shooting through while closing the one on the opposite side, and it switches back and forth. Still, it's a mistake).
Continuity mistake: At the beginning of the episode when Buffy and Willow stop at Buffy's locker, in the first shot, Willow has her backpack strap on her shoulder and takes it off. It then cuts to another angle and Willow's backpack strap is back on her shoulder, and she takes it off a second time.
Continuity mistake: In the beginning dream sequence, when Buffy is surprised by the Master and backs up into the wall, watch her two pigtails. As the scene cuts back and forth between Buffy and the Master, her pigtails move from behind her shoulders to in front of her shoulders and back several times. First they're both behind her shoulders, then only one is behind, then both are in front, then one moves back behind again, etc. Obviously multiple different takes were cut together in editing.
Continuity mistake: In the scene where we see Buffy's mum drop her off at school, when Buffy is worrying that her dad will not show up, we firstly see Joyce's seatbelt is on. We then see her again and it is still on. However after the shot goes back from Buffy to herself, we can see her seatbelt is off. Then when the shot comes back to her again it is back on.