Now this is a bit of an obscure oddity; my first experience with this flick was tuning into it by accident one Sunday afternoon while young - my best guess would place it sometime between 1968 to 1972 - and I was immediately grabbed by the image of a badly disfigured man loading two people into a chamber and turning a valve which filled the chamber with a gas that somehow turned them into skeletons (perhaps he hung out with the villainous Dr. Bartell of The Flesh Eaters). That was all it took to engage my 12 year-old sensibilities. Years later, as with so many other films, I tracked it down. To answer the obvious question "Was it worth it?", the answer is a little yes, a lot no.
It should be mentioned that the station in question was the seriously underfunded NBC affiliate in Corpus Christi. It was unusual for them to show any horror movies, and when they did, they were usually of the caliber of Giant From the Unknown and Frankenstein's Daughter. These are apt companions for Castle of Evil.
First, we must understand that there is a particularly unpleasant dude named Korvik who is some sort of electronic genius/unscrupulous millionaire/owner of a castle somewhere in the Carribean (I guess). Two years before the events of our story, one of Korvik's experiments went awry and exploded, burning him with "phosphorus salts" and condemning him to a slow and particularly painful death. In the present day, six former associates arrive at the island (in the midst of the requisite storm) to hear The Reading of the Will (*snicker*).
Our cross-section of humanity includes a disagreeable shyster lawyer (David Brian); a singer/former Korvik love, Sable (Virginia Mayo, who is introduced to us singing an a capella version of Frankie and Johnny, making us all hope she dies quickly); Doc Corozal (Hugh Marlowe), sued for malpractice after saving Korvik's life; Tunki (Ernest Sarracino), a native chieftain whom Korvik ripped off; Matt (Scott Brady), two-fisted hero; and Carol (Lisa Gaye), Matt's former love interest. They are met by the enjoyably evil housekeeper Lupé d'Esperanza (Shelley Morrison), who reveals that Korvik believed one of them was responsible for his accident and resulting death. Nobody gets a chunk of his estate unless they figure out who.
All this might have resulted in a sort of pared-down Ten Little Indians, except that the whole thing is part of a warped Korvik revenge scheme orchestrated by Lupe and involving a Korvik look-alike robot intended to kill off our merry band one by one, starting with the lawyer (huzzah!). Cropping up where least expected, thanks to a network of secret passages, the Korvikoid next attacks Lupé, much to her chagrin. Somehow, after a few minutes, Lupé comes back to life just long enough to explain the plot to Matt and Doc (she was the one responsible for the accident, and was trying to get the money for herself by offing everyone else, but alas, the robot's "brain is a computer...filled with all the evil that is Korvik!").
The gang barricade themselves into a bedroom (admittedly of limited effectiveness in a building riddled with secret passages) while Matt and Tunki explore the bowels of the castle, discovering control rooms, labs, and an extremely convenient laser that is used to put the Korvikoid to rest while he's chasing Carol around in her gothic romance nightgown. The end.
If there is one major thing wrong with Castle of Evil (past the über-cliché setup), it is the fact that the movie is determinedly unscary. It shows its origins as the bottom half of a double bill that parents could safely leave the kids at on a Saturday afternoon. It seems an odd thing now, but it was 1966, and most of the fare that showed up on these double bills were fairly innocuous - until 1968 and Night of the Living Dead shook up that cozy little tradition. *
The only two people that die in Castle of Evil are the two that really deserve it - the despicable lawyer and the evil Lupé - no matter how much we pray for Sable's demise with each successive wisecrack. The impressive Korvik makeup (the best half-face since War of the Collossal Beast) and the Skeleton Gas are more geared toward making a Jujube-besotted crowd go "Eeeeeew!" than scream. There is, in fact, an odd lack of drama in the whole enterprise - it all seems much more perfunctory than purposeful.
The structure is certainly there - things proceed more or less logically (except for the "You just saw a walking corpse? Better put on your nightgown!" scene), and each character's back story is introduced at a dramatically appropriate time. It's just that there is a complete and total absence of zeal in any form anywhere - and that is the Kiss of Death for a Bad Movie.
In fact, Castle of Evil would have worked much better as a stage play - and that's about the worst thing you can say about a movie.