The following review is an extract from the book "Santo, the Wrestler with the Silver Mask: A guide to all his films", which is now available on Amazon.
"In this part of the Saint we have condensed in just over 80 minutes the classic monsters of the cinema, all in a single film. Here, these beings are automatons without their own will, which at all times follow the orders of the usual mad scientist - an archetypal character of science fiction B movies in general and of Santo´s films in particular. The vampire and the mummy correspond to the usual aesthetics, and so does the "Franquestain" (whose name is written like this during the presentation in the credits), with its markedly "Karloffian" aspect. The werewolf, on the other hand, looks more like a bearded vampire, while the "cyclops" is powerfully reminiscent of the "creature of the black lagoon"; it is a scaly, amphibious beast with a single phosphorescent eye. We also have zombies (if the professor's greenish lackeys can be considered as such). One of them is characterized by wrestler "Caveman" Galindo. Another monster also appears in the laboratory, which although it has a secondary role, is striking: It resembles the aliens in Tim Burton's "Mars Attacks", a film that would not be made until 26 years later.
(...) It is curious the confusion between day and night in certain sequences. For example, during the car chase, one moment you see the daylight and the next moment it is suddenly night (!). Or when the entourage of henchmen of the mad scientist arrives at the castle with his corpse to revive it, they go in a carriage carrying torches... when it is clearly visible that it is daytime...
If up to now Santo used to be enraptured by an aura of mystery, by a certain intangibility, now there are shown moments of his private life: Like his courtship with Gloria (whom he kisses with the mask on!)"