Continuity mistake: In the rooftop scene, Buffy's hair is partly tied back and slightly curly but by the time she reaches the Police station it is completely loose and much curlier.
Revealing mistake: When the insect creature is crawling on the ceiling its hair doesn't falls down towards the floor, it "falls" towards the ceiling. (00:22:05)
Answer: Nope, it's not Darla - that's Rachel from the episode "In The Dark", the third episode of the show (the one with Spike's magnificent opening monologue).
Tailkinker ★