Buffy runs through "Hell" being chased by demons. She starts out wearing running shoes. They change to canvas sneakers and back to running shoes again during the chase. As she climbs the top of the ladder they are different shoes altogether.
When Buffy wakes up from her dream, she is wearing her cross. When she gets up and goes to the window, the cross is gone.
Buffy has left Sunnydale. However when she is going though the blood bank records the form asks for parental consent to give blood to the Sunnydale blood bank. It is also spelt incorrectly as Sunnyvale.
When Buffy is hit by a car, you can see Sarah Michelle Gellar's/the stunt person's knee pads quite clearly as she is bounced off the hood.
When Buffy is knocking demon guards off a platform, you can see that they are landing on safety mats.
Even though Ricky is said to have lived a long time in the demon 'hell' his tattoo looks fresh and new.
When Buffy throws a demon off of the platform near the end of the episode, you can see the pad for him to land on.
When Buffy is screwing on the lids of the sugar dispensers she doesn't screw the first one on properly.