Following the release of "City of the Living Dead", Fulci decided to continue that film's exploration of metaphysical concepts--in particular, the ways in which the realms of both the living and the dead might bleed into each other.
Following the release of "City of the Living Dead", Fulci decided to continue his exploration of the concepts of hell that were at the heart of "City of the Living Dead". In particular, the concept of the metaphysical way that the realm of both the living and the dead bleed into each other.