The only spoken dialogue in the film appears only in the last scene, which features Lee reading from Bram Stoker's original novel.
"Cuadecuc" is Catalan for "worm tail", so the title translates as "Worm Tail, Vampire".
The entire film is photographed on high contrast black & white film stock, which gives it the appearance of a degraded film print, evoking early Expressionist horror films such as F. W. Murnau's Nosferatu or Carl Theodor Dreyer's Vampyr. It was shot on the set of Jesus Franco's Count Dracula, starring Christopher Lee and Herbert Lom.
The opening credits describe Jess Franco's Dracula as a Hammer film. It was not.
Christopher Lee would appear in another Portabella film the same year--Umbracle.