James H. Nicholson had come up with a tremendous ad and title and pre-sold the movie to exhibitors. Then they made the movie. When the distributors viewed the finished film, they were disappointed because the ads were so much more interesting.
According to American International Pictures head Samuel Z. Arkoff, Roger Corman's contract called for four films at a budget of $100,000 each. By the time it came to "The Beast with a Million Eyes," the fourth film in the series, there was only $29,000 to $30,000 left, so Arkoff signed off on shooting the picture non-union in Palm Springs.
Because of budgetary considerations, the "monster" ended up being a teakettle with a lot of holes in it.
The tiny budget meant music, credited to "John Bickford", is actually a collection of public-domain record library cues by classical composers Richard Wagner, Dimitri Shostakovich, Giuseppe Verdi, Sergei Prokofiev, and others, used to defray the cost of an original score or copyrighted cues.
Producer Roger Corman was unsatisfied with the way the film was progressing and took over from director David Kramarsky, without credit.