(at around 9 mins) When Willow is at the police station taking the building apart, three policemen run out and point guns at her, ordering her to stop, and a woman and a man in the background run out of the building. After Buffy runs in and makes her way upstairs, the same scene repeats about a minute later while Willow is still outside, with the three policemen and couple running outside in the background.
As Willow is pulling pieces out of the jail wall, the number and placement of bricks removed changes repeatedly.
At 4:19, Jonathan is standing with his back to the bars of his cell, but when the view cuts to a wide shot he's suddenly is standing at an angle with one arm wrapped around a bar.
As Willow starts her "little tour" at 20:34, she has her right hand on Rack's face and her left hand on his chest, but when the view cuts to a different angle her hands are switched, with her left hand on his face and her right hand on his chest. Also, Rack's right hand, which was touching Willow's face before the cut, suddenly is down by his side.
When Willow is "lifting" Rack up you clearly see his legs stepping up some off screen steps to make it look as if he's being lifted.
You can clearly tell that Buffy and Willow are really being played by stunt doubles.
Andrew puts his sword on Xander's throat, and you can clearly hear a sound of the sword been pulled out of a scabbard. However, Andrew already had his sword up. A couple of shots later, Jonathon puts his sword against Andrew's neck; same thing.
When Willow is destroying the jail cell wall, a person can be seen briefly pulling away one of the bigger sections of the wall.
At 8:46, as Willow climbs through the hole in the wall, shadows moving on the "cityscape" behind her make it obvious that it is a TransLight background.
Jonathan tells Buffy and Xander that he's known Willow almost as long as he's known them. Willow and Xander grew up in Sunnydale with Jonathan, while Buffy only moved there in 10th grade, so he should have known Willow and Xander longer than Buffy.