Joyce is released from the hospital, she is on her feet. Most hospitals in the state of California have patients released from the hospitals in wheelchairs by orderlies.
Before the title sequence, when Dawn is sitting with Joyce in the hospital, Dawn can be heard talking about how Jell-O is made but she can be seen on the left of the screen absent-mindedly eating (and not speaking).
(at around 57 mins) Willow begins to say "Uh guys, I've got some stuff" but her mouth is closed for the first couple of seconds.
(at around 40 mins) Willow, Xander, Tara, Anya and Giles leave Riley to continue checking out the scene, but someone in a beige coat standing to the left of the frame can be seen.
Willow refers to the Tunguska Blast of 1917. In fact, that event occurred in 1908.