Continuity mistake: When Buffy is discussing the Turok-Han with the potential Slayers in her dining room, one of them says that it almost killed Buffy. Rona then spreads both her arms out and says, "What chance do we have?" In the following shot, her left arm is down by her side and her right arm is resting on the dining room table.
Other mistake: When The First (disguised as Eve) tells the Turok-Han to kill everybody except Buffy, it runs past her towards the exit of the crypt. The First then says, "Well, alone again", turns to face Spike and transforms into Buffy. In this shot, the Turok-Han can be seen still leaving the crypt, even though it had plenty of time to reach the exit and was running towards it at full speed.
Audio problem: When Giles and Anya are talking to the demon, trying to get him to open the portal to Beljoxa's Eye, when you see Anya's face from the side, her lips don't sync up with what she is saying, and sometimes her lips are moving to words when she doesn't have any lines at all.