This movie ranks in my top five all time of over 8000 movies I've seen. My other top four hour before the Devil knows your dead with Rochester New York's Philip Seymour Hoffman. Sherlock Holmes smarter brother with Gene Wilder Dom Deluise and Madeline Kahn. No country for old man with Javier Bardem and Lucille fulcis beyond the door and Autopsy from 1975 and Death Laid an Egg from 1968.

Master Mario Bava Directs and Shoots another Film that Transfigured and Ignited Horror Cinema in the Decades to come. This is Without Doubt (so many times these sort of proclamations have doubt) the First "Slasher" Film. Hitchcock's "Psycho" (1960) can be Sighted as a Spark but without the Fire that Bava sent Blazing. It's a Sub-Genre of Horror that Survives to this Day. It has Survived Critic and Parental Wrath and Disdain and is one of the most Profitable.The Movie is Famous for its Body Count (13) that was used in Advertising Campaigns, Bloody Gore, No Redeeming Characters, Excellent Makeup and SFX, Haunting Mood and Cinematography (Bava), Fast Pace, and an Ending that No "Body" saw coming.Viewed Today it seems Familiar, due to the Hundreds of Imitations and Followups Churned Out in the last 35 Years. Bava's Emphasis Turns to Blood Bathing and Gruesome Gore after He Reinvented the Gothic Gloom Cinema in the Sixties.He Ushered in the 1970's and Wrote the Training Manual that made a lot of People a lot of Money. Mostly Hacking the Maestro with Little Style and Wit and No imagination with Eyes Only on Box-Office Receipts.The "Slasher" Genre does have its Restraints with Repetition Punctuating the Pictures and One Upmanship the Order of the Day. Objectively even Bava's Movie is Missing certain Elements of Plot, Character Development and Overall Concern for Complexity. The Checklist Style, Invented here, has made "Slashers" the most Guilty of Guilty Pleasure Exploitation.

Just as the giallo was gaining popularity, Mario Bava proves he's way ahead of the pack by turning the genre on its head, then kicking it up and down the street a few times for good measure. This is evident from the first murder of the film. At a moody, almost deserted bay, an old lady in a wheelchair stares out over the water longingly at a small wooden shack. Sighing, she turns to go to bed for the night when a noose is thrown over her head and she's hung from a doorway. A black gloved killer stands above her body, but just to let you know this is a Bava film, the camera pans up to immediately reveal his face, and just to further let you know this is a Bava film, someone kills the killer by stabbing him to death!Most gialli have one killer, some have two, Bay of Blood has at least five or six, all of them with the same intention: to gain ownership of the bay, which would provide them with great wealth. There's the businessman and his girlfriend who have some shady deals going on, then there's the second victim's daughter and her husband (and their kids, who they brought along for some reason), then there's Simon, who is the old lady's son, and likes chewing on raw squid. Innocent bystanders are a local Entomologist and his tarot reading wife, and a bunch of annoying hippies who have turned up to have fun. Bava barely even bothers with any kind of plot for the first hour of this one, and is more interested in turning part of the film into a slasher movie, seven years before Halloween was released. The hippies are first and I'm sure it was a shock back then to see someone receive a giant blade directly to their face, followed shortly by a couple being speared through the back right in the middle of a bit of filthy squeezy. As mentioned everywhere else on the internet, there are a lot of similarities between this film and the first two Friday the 13th films, as well as a lot of similarities between this review and every other review of this film. Eventually the cast is whittled down enough to allow time for some flashbacks that films in the gaps regarding who is doing what to whom and why, and Bava also throws in a 'what the feck?' ending. This is barely a giallo and more of a comedy of the darkest kind about greed.

Mario Bava's highly regarded "Reazione a Catena", which translates as "chain reaction" in English, is rightfully considered one of the principal inspirations for what would become the "body count" horror movie. Here, we have characters often sharing one common trait: unbridled avarice, as they scheme to get their hands on a prime piece of bay side property coveted by all. To meet this end, people are quite willing to kill each other, and any & all potential witnesses to boot. The movie is co-written and photographed by Bava, and it bears the mark of the director's work by being extremely striking visually. Once the haunting music courtesy of Stelvio Cipriani is added, we get an effective melding of soundtrack & image. Right from the start, this aesthetic is stressed with the opening credits. The scenery is certainly beautiful, and the "prowling" camera-work also adds to the experience. It would be fair to say that these elements take precedence over an admittedly fairly simple story. The first nine minutes play out without using any dialogue, and they're riveting. It's hard to forget that image of a squid slithering over a dead body's face. Of course, many adoring horror fans love this movie for its treatment of all cast members as fair game. The gore is very well done - it was the work of future Oscar winner Carlo Rambaldi, who went on to work on such films as "King Kong" '76, "Alien", and "E.T.". If one has seen such slashers as "Halloween" and "Friday the 13th" parts 1 and 2 before seeing this film, they'll right away notice how "Reazione a Catena" influenced them. The acting is pretty good, from such principals as Claudine Auger ("Thunderball"), Luigi Pistilli ("The Good, the Bad & the Ugly"), Claudio Camaso ("Vengeance"), Laura Betti ("Hatchet for the Honeymoon"), and Isa Miranda ("The Night Porter"). Brigitte Skay ("Homo Eroticus") supplies some full frontal nudity as a bonus. Overall, this is a fun film, which keeps the carnage going right up until the very end, with a delicious denouement. It may not be among the best of Bava's work, but its status is undeniable and it's nothing if not entertaining. Seven out of 10.