Possibly the biggest challenge in watching this Spanish/French horror extravaganza is the dubbing. As is sometimes the case, less than a scrupulous translation of the dialogue can produce unintentionally hilarious results. Some would say that adds to the charm. Perhaps they are right.
You may be led to believe this is a Jess Franco production. I was. It is in fact directed by Pierre Chevalier who delivers a comparatively accessible yarn filled with genre cliches used to fairly good effect. Once again playing Orloff is the mighty Howard Verson (who had played the character for Franco before, and would do so again in the future), the hero-type is Dr. Garondet (Frances Valladares), and the vampy young lady of the piece is Cécile (Brigitte Carva). If you're ready, there's also an invisible ape who gets up to all sorts of nasty business - again, some of his vile antics do unintentionally (I presume) raise a smile.
The story seems to have bits and pieces from most of the horror classics thrown in. You might recognise elements from Dracula, and Frankenstein, and there are dark tunnels and a hero who delights in wearing a red-lined cloak. It's all here and is delightfully unconventional in places and darn right ridiculous in others.