When Buffy pushes Spike to the ground outside The Bronze, his coat slips on and off his shoulders between shots.
When Dawn is covering for Buffy about the rubbing alcohol, there is a bottle of what looks like Betadine on the stool. When Joyce leaves the room the other bottle is gone from the stool. Dawn then hands Riley the rubbing alcohol slightly off camera, but when the shot switches back to him he is placing both bottles on the floor.
Spike, in 1880, is shown as being left-handed whilst writing. Right up part way through the 20th century left-handedness was largely forcefully suppressed during schooling, including corporal punishment to literally "beat" it out of the child. Spike, as an upper-class, educated, youth would not have been allowed to be left-handed.
Spike, Dru, Darla and Angel are seen calmly walking among street chaos during the Boxer Rebellion in China, without being disturbed. However, the rebellion was, precisely, against foreigners' presence. Four well dressed, upper class and not particularly threatening looking Europeans (two of them women) could easily had been targeted by Chinese radicals, although with deadly consequences for the attackers.
When Spike is pushed onto the ground by Buffy outside the Bronze, after they fight, his mic pack is visible on his left side.
(at around 8 mins) For several seconds the transmitter clipped to Spike's belt is visible.
As Act I opens and Buffy goes running off through the graveyard, the mast of the mobile lighting tower that is illuminating the scene is visible several times against the dark sky beyond the cemetery wall.
At 8:19, as Giles says the "D-word," the glass front of the display case beyond his left shoulder reflects something moving off-camera, likely the boom operator maneuvering the boom microphone.
At 28:02, when the camera circles around Spike to pick up Buffy, you can see the tip of the boom microphone come into frame as well, bobbing above her head.