Continuity mistake: In "Becoming Part 2" At the end when Spike chokes Drusilla unconscious, he picks her up, one of her hands is resting on her stomach and the other is hanging to her side. It cuts to a shot of Spike looking at Angel and Buffy fighting then to Spike leaving with his back facing the camera. You can see that the hand resting on Drusilla's stomach moved to Spike's shoulder.
Continuity mistake: In the season two episode, 'When She Was Bad', in the scene where Buffy smashes the masters skeleton with a sledge-hammer she smashes the rib cage to pieces. Suddenly the rib cage has again become completely intact and she smashes it to hell again. (00:40:35)
Plot hole: Giles tells Willow to leave him while he extracts information from Ethan on how to break the costume spell. By the time Giles smashes the statue Willow has already found the others, who had left the house where she thought they were and are hiding in a completely different area of the town. No matter how long it took Giles to beat the information out of Ethan, there is no way Willow could have gotten back to the house, realised they were gone and tracked them down before the spell was broken. As a ghost, it is possible she could have happened across them even though they were hiding, but seems unlikely.Shay
Factual error: When Angelus is torturing Giles in this episode he is seen with Giles' glasses, and he cleans them by breathing on the glass and wiping with a cloth. Vampires don't have breath, as Angel tells Xander in 'Prophecy Girl' from season one - even if he can force some air out of his body, it wouldn't be warm, moist air, which is needed for condensation to clean glasses with.
Plot hole: Willow and Cordy disappear during a vampire attack. We later see that they spent the entire night hiding out in a closet, but wouldn't Buffy have gone looking for them once the vampires were gone? She knew they had run off somewhere (she mentions it to Giles when she gets a stake from the library). Instead she just goes home, leaving them still missing as far as anyone knows. (00:41:25)Shay
Continuity mistake: When Buffy wakes up she is wearing metallic nail polish, yet when she went to sleep previously, she has no nail polish on. Later in a scene where Buffy is dreaming about her night with Angel she has the nail polish on again, even though that took place the night before when she did not have her nails painted. (00:01:15)