Revealing mistake: When Buffy, Spike, Andrew and Robin go to the high school and find it decimated, Buffy is thrown to the ground and attacked with a hockey stick. On the second swing, a sound effect is heard and Buffy falls over. But the hockey stick never makes contact with her.
Continuity mistake: In the scene where Xander and Anya have had their "one more time" and are lying in the cellar bed talking, the shot is on Xander and he is speaking. When he finishes speaking Anya starts, but the camera stays focussed on him, however, you can see part of Anya's face in the shot and her mouth is not moving despite the fact she is talking.