When The First appears in the basement as Jonathan's corpse, the first shot show him with his right eye all white and decomposed. In the next shot, its the left eye that is missing.
When Buffy goes to save Xander from Lissa, she knocks a dagger out of her hand and it is thrown to the ground near the far end of the room. Two shots later it has moved closer to the door.
When Buffy drops to the ground at 20:19 after staking the first of several vampires, her hands are suddenly empty - she is no longer holding the stake she just used. However, as she jumps to her feet to continue the fight, the stake is just as suddenly back in her hand.
When Buffy and Wood first see the first vampire come around the corner in the alley, the shot is actually stock footage from The Gift (2001). (It was the vampire from the beginning of that episode.)
When Buffy and Wood first see the first vampire come around the corner in the alley, the shot is actually stock footage from The Gift (2001) (the vampire from the beginning of that show).
In the graveyard scene when Cho-Anne says, in Cantonese, "I don't understand what any of you are saying," she starts to mouth part of the line early, but we don't hear it.
As Buffy, Principal Wood, and Spike leave the restaurant in Wood's car, Wood eyes Spike sitting in the back seat suspiciously in the rear view mirror. Spike is a vampire, he would cast no reflection in the mirror that Wood is looking into. Additionally, later in the episode Wood is surprised to learn that Spike is a vampire. This would not be the case if Wood couldn't see him in his rear view mirror.