Complex sentence: The film was completed in 1959 under the working title "The Black Door" but was not theatrically released until May 3,1962, when it was released under its renamed title on a double bill with "Invasion of the Star Creatures".
Split into simpler sentences: The film was completed in 1959 under the working title "The Black Door" but was not released until May 3,1962, when it was renamed. It was theatrically released in 1962 on a double bill with "Invasion of the Star Creatures".