The viewer is expected to determine who is wearing the masks in this episode. It leads one to wonder that if kids wear monster masks on Halloween, then what kind of masks do the monsters wear? It is fun, lighthearted, and for it's time, portrayed vampires in a uniquely different light. You'll find no capes or fangs or fake Transylvanian accents here. As Karloff says in his intro, "Before this terrifying adventure is ended, you'll change some of your outdated ideas about vampires."
This episode is appreciated even more on second viewing after seeing the reveal at the end, as much of the dialogue is cleverly written and will take on new meaning. Elizabeth Montgomery and Tom Poston play well together, and the lighting and detail in the house is a pleasure to watch. It looks as though Norman Bates left behind objects of his taxidermy. There's much to enjoy about this episode.