Continuity mistake: While studying at the Bronze, Buffy and Willow leave their books on the table to go and dance. Spike calls them outside to fight a vampire, and when Xander runs back inside to grab a stake the books have all been put back into Buffy's bag. (00:14:00 - 00:15:45)
Continuity mistake: When Buffy's fighting Spike at the end of the episode, there are times when it's obvious that it's James Marsters' stunt double. Spike's hair is platinum blonde, slicked back, and all one length in the back, while the stunt double's hair is more brassy, spiked in the front, and layered in the back.