The producers decided to use the very heavy make up on Duncan 'Dean' Parkin as a way to disguise the fact that a different actor was playing Col. Manning, especially since in a dream sequence flashing back to the original film featured Glenn Langan, the star of that film.

The final scene of the film, lasting less than one minute, is in color.

American-International changed to title to a more dramatic-sounding "War of the Colossal Beast" and avoided mentioning in the ad campaign that it was a sequel to an earlier film.

Throughout the movie Col. Manning says only one word: the name of his sister, "Joyce".

This was originally released as part of a pre-packaged double feature with Six Inches Tall (1958), another film by Bert I. Gordon.