The corpse that Willow is lying next to alternates between its eyes being open and shut.
As he leaves for the High School with Xander and Willow, Spike is wearing cut-off khaki shorts. When they get to the High School, he's wearing blue jeans.
Willow crawls across the bed (in the dark) from the right hand side to lie down on the left side. When the light comes on the corpse she's lying next to is on the right hand side of the bed. She would have had to crawl across the corpse to get to where she was lying.
At 35:38, you can see Spike sitting in the background with his vampire face on. In the next shot, Spike's face is normal again.
At 36:37, Spike is shown holding the bag of bones thrown to him by Willow. The view then cuts to Buffy fighting, and Spike can be seen sitting empty-handed in the background. When the view cuts back to him, he has the bones again.
The rat playing Amy is male.
At 33:00, in the high-angle shot of Giles being lifted over the demon's head, there is a moment when you can see the studio roof over the top of the set.
At 31:20, outside the Historical Museum Sunnydale as Spike walks away from Willow and Xander, the camera rails are clearly shown on the right of frame.
At 36:57, when Willow and Xander help Spike up off the floor, a camera is clearly visible on the left covering a full third of the width of the screen.
37:07 When Buffy throws the last demon and it rolls, something that looks like a crew member's arm in a light blue sweater is visible in the bottom left corner of the screen.