Trivia

Paul's shirt in the film indicates he is an alumnus of Miskatonic University, an institution that features prominently in H.P. Lovecraft's stories and one of the settings in Resurrección satánica (1985), the first Lovecraft adaptation by director Stuart Gordon, producer Brian Yuzna and writer Dennis Paoli.

Dagon appears in the Judeo-Christian Bible and is the name of a half-fish/half-man deity who is the father of Baal. Dagon was worshiped by the Assyrians in Ninevah, whom the prophet Jonah was sent to preach to.

The majority of this film was shot with a hand-held camera.

In "The Shadow Over Innsmouth" the cult of Dagon was lead by the Marsh family. In the movie, the cult of Dagon is lead by the Cambarro family. They were named after Combarro, the coastal Galician town where the movie was filmed.

When Paul and Bárbara come close to Imboca, both see strange buildings supported over four pillars with a trident symbol on the roof. These buildings are actually raised granaries ("hórreos" in the original Spanish), a typical building in the north of Spain used to keep the harvest collected during the summer and preserve it for autumn and winter. Raised granaries are crowned by the Christian cross, changed for the movie to the symbol of Dagon's cult, a trident. When the movie ended, the tridents were retired.