Margheriti is best known to horror fans for directing the marvelous "Castle of Blood" with Barbara Steele and its remake, "Web of the Spider," with Klaus Kinski, both atmospheric, Mario Bava-style ghost stories. So it seems odd that in 1980, Margheriti (who directs under the pen name Anthony Dawson) would jump on the cannibal bandwagon. In the late '70s, cannibal films such as "Cannnibal Ferox" and "Cannibal Holocaust" were tearing up the box office in Asia and parts of Europe. This is Margheriti's contribution to the genre.
On the plus side, the film is a nice slice of late '70s culture, with a cheesy disco-fied score (which even picks up with its groovy beats when cannibals start carving up a body), and the always-welcome presence of John Saxon. On the negative side, it isn't really a horror film or even much of a cannibal movie, more of a "rabies" film. Anyway ...
Saxon plays a Vietnam Vet with memories of a horrific incident he witnessed rescuing POWs back in the war: Some of his buddies behind Vietnamese bars had turned cannibal! Back in the U.S., one of those old cannibal buddies (veteran exploitation actor John Morghen, who also starred in "Cannibal Ferox") gets in touch with him to shoot the breeze. Not soon after this, the troubled friend goes crazy in a movie theater and bites a woman who is being sexually ravaged by her boyfriend.
One thing leads to another, and the police are pitted against the deranged Vet, who's holed up in a shopping center. He is captured, but hooks up with yet another one of the cannibalistic Vets in a mental asylum. They begin a break out, eating some people, and only biting others. The ones who are bitten and live become cannibals themselves! Eventually, Saxon himself becomes a cannibal, wreaking havoc on his marriage.
"Cannibal Apocalypse" plays a bit more like an action movie with gore than a fear film. It's well loved by fans of exploitation fare from the '70s, but if you're into extreme cannibal mayhem, you might want to look elsewhere, and even if you're into horror. But it was an interesting diversion for Margheriti.
It was first released on VHS in the U.S. in a terribly cut form under the title "Invasion of the Flesh Hunters." The version to seek out is the DVD released around 2000, which is fully uncut and loaded with special features that treat the often-derived film with the reverence of a lost masterpiece (which it isn't).