The heads of the "Boris" and "Monster" figures are the same basic shape, appropriately enough, with Boris' fine-tuned for a more human appearance and the Monster's for that monsterish look (look at the figures' heads when they're in the same shot, both more or less in profile, during the "greeting the guests" scene).
The producers of this movie did not want to pay for the use of the names "King Kong", "Frankenstein's Monster", "The Bride of Frankenstein", "Quasimodo" and "The Creature From the Black Lagoon". That is why in this movie the character of King Kong is called "It", Frankenstein's Monster is called "Fang", The Bride of Frankenstein is called "The Monster's Mate", Quasimodo is called "The Hunchback of Notre Dame" and The Creature From the Black Lagoon is called simply "Creature". The names "Count Dracula" and "The Invisible Man" were in the Public Domain at the time the movie was produced. Since no fees were required for their use, they were used in the movie.
Before Lionsgate's video release, almost all video releases have been from 16mm film and were of very poor color quality. The original film negative was water-damaged some years ago, but recently Sony Pictures Television (which now holds the television rights) unearthed an original 35mm pristine print. This print was digitally remastered, and is the source for the DVD issue and all subsequent television showings.
In her stand-up comedy routines, Phyllis Diller (The voice of The Monster's Mate.) referred to her husband as "Fang". She decided to use that name when referring to the character of Frankenstein's Monster whom her character is married to in this film because that is what she is used to. The producers decided to allow that since the name "Frankenstein's Monster" was copyrighted and use of it would have required them to pay for its use.
Although it was constructed in academy ratio (1.33:1), the film was intended to be screened in a 1.85:1 widescreen aspect ratio. It has never been released in its intended aspect ratio on either television or home video, not even on Blu-ray. However, the widescreen ratio can be obtained on 16x9 televisions by using the Zoom 1 setting.
The credits in the main title advertise an "original sound track score by RCA Victor Records." While this was indeed the plan in 1967, the film's failure at the box office led RCA Victor to shelve the LP's release. The mastering of tracks had already been completed, including all of the film's instrumental cues and vocal performances by Boris Karloff, Phyllis Diller, Ethel Ennis and Gale Garnett, and they languished in the company's vaults until Percepto Records unearthed and released them on compact disc in 1998. That release is now out of print and commands a hefty price. In 2016, Waxworks Records finally issued the sound track score on LP in a special edition colored vinyl issue.