When Buffy and Joyce are eating dinner, Joyce's dinner plate disappears between shots, and the large yellow salad bowl jumps from one end of the table to the other.
In the opening scene, Riley's elbow is next to Buffy's head in her close ups, but by her side in the wide shot.
At 23:00 there's an outside day shot of Buffy's house and the actual address of 1313 can be seen instead of Buffy's 1630.
The beach barbecue is constructed out of cinder blocks which are made out of concrete - not the material of choice for a public fireplace since due to the water trapped in its structure, it can violently crack under the heat, throwing hazardous debris around.
A water bottle is visible on the mantel in Dracula's mansion, adjacent to more Dracula-appropriate urns and candles.