Episode Five - S1-E5
Revealing mistake: The mirror over Barnabas' mantel hangs flush against the wall. Yet when he shatters it, the candlestick he throws can be seen to go through the glass instead of bouncing back as it should have done. (00:43:45)
Episode Ten - S1-E10
Revealing mistake: Willie kneels beside Barnabas' coffin in the secret room. The only opening is the single door behind him, but the light source for the lightning flashes illuminating the room comes from behind the camera, where there should be nothing but a solid wall. (00:10:30)
Episode Six - S1-E6
Revealing mistake: A vampire-entranced Carolyn uses a butcher knife to push open Julia Hoffman's bedroom door. The wood is otherwise pristine, but near the knife's point, you can see scratch marks left by the knife during previous takes. (00:30:15)