This is a Japanese monster movie. From what I've read it's like a tale of these weird monsters that is widely known in Japan. This movie is a great movie to see if you like any kind of Japanese cinema. This film along with it's sequels (4th one directed by Takashi Miike) are available through Amazon.
Japanese Title: Yôkai daisensô
Please visit the "Cinema Corpse" videocast on iTunes. They review horror and sci-fi movies and add a little humor in the mix. Also can be found at http://cinemacorpse.podomatic.com