At around 36'50", you first see the exterior of the Watchers' Council building. The aspect shown is a curved exterior set back in the corner of the building. When the building is shown exploding at around 38'25", the building is similar but clearly different. It is now no longer curved but right-angled and a lot grayer than the previous sandy colour.
When Principal Wood rolls the corpse of Jonathan into a grave and begins to shovel dirt down on him, Jonathan slightly winces and flutters his closed eyes.
At 33:16, you can clearly tell that it is not Sarah Michelle Gellar stabbing the intruders but instead her stunt double because of the much tanner and more muscled arms.
When Buffy comes into the hallway (where Anya and Xander are discussing how they will interrogate Andrew) and closes the door behind her there is the sound of the a door closing to, yet the door behind her never fully shuts.
During Buffy's conversation with The First disguised as Joyce, Xander can be seen in the background sweeping several inches above the floor.