Antropophagus (1980)

A group of tourists become stranded on an uninhabited island where they are stalked by an insane, violent, and grotesque killer that slaughtered the town's former residents.

From memory: Infamous, controversial, often banned or drastically cut shocker isn't really a good movie, but it cleverly upped the ante of gore considerably.

Maltin:*1/2: "Trifling shocker."

L'anticristo (1974)

A paralyzed young woman with serious mental problems stemming from the death of her mother has a crisis of faith, and the intervention of a well-meaning psychologist leads her to remember her past life as a witch during the Inquisition.

No holds barred rip-off of The Exorcist is wildly exploitative, but offers some truly cinematic touches with great cinematography (by Joe D'Amato!) and some genuinely surreal sequences.

Maltin BOMB: "Frenzied but pointless rip-off of THE EXORCIST..."

Michael Weldon/Psychotronic: "It took a while to get here, but this was the first blatant Exorcist copy produced...the usual bile, floating bodies, and an orgy in hell."