Psi (psychic) vampires and sanguinarian vampires are mentioned in this ep. This site has links to other sites featuring the two types.
The poen Vampir is reading is "The Vampyre" by John Stagg.
When Boy 1 tells Goth 1 to turn into a bat, his voice is that of Boy 2: much deeper.
Henrietta tells the Vamps to put their Banana Republic clothes back on. Little did she know that Banana Republic was replaced by Hot Topic until later.
When Steven gets pissed off about something in his coffee, he pulls a spoon out, but another spoon appears out of nowhere in his cup. Now he has two of them.