Continuity mistake: Towards the end of the episode whilst Buffy is fighting Caleb with the scythe, right after he says to her, "You're not slipping out of this fight, girl. Can't you see? You can't stop me. I can just keep going back for more. It's like being reborn," and throws her into a wall, the position of the scythe changes constantly between shots.
Continuity mistake: At the beginning of the episode when the Potentials are fighting the ubervamps, when they see the second one they move away from it. You can see in the bottom right hand corner of the screen that the ubervamp already has a Potential. In the next shot you see it jump down and grab a Potential.