Fifteen (or twelve, depending on whether you believe an onscreen title or a leading character) years after four teens were brutally murdered at a mountain camp site, a fresh batch of young blood arrive to spend a weekend drinking and dancing any dying and dancing and drinking. To say that the remaining characters seem unpreturbed by their ever-dwindling number would be putting it mildly. As such, there's zero investigative element to proceedings; characters couple off, shower and die. The camp site's owners, David Hess and Mimsy Farmer, have a loveless marriage which was somehow survived fifteen years of her cheating with the local sheriff and his obsession with catching the Indian shaman who allegedly haunts their land.
Slasher movies tend to fall into one of two camps*; those with killers of a vaguely supernatural bent, whose identity is never in question (Halloween, The Burning, most of the Friday the 13th sequels), and those with human killers who are unmasked at the climax (My Bloody Valentine, Graduation Day, one of the Friday the 13th sequels). Many of these latter killers take advantage of local legends, channelling mythical figures as a cover for their actions, and to spread fear through the community. Body Count, if we set aside the final scene for now, falls into this category, with the killer dressing up as the aforementioned shamanic figure.
The characters are of a college-going vintage, which places them at the high end of the slasher age spectrum. They're much younger than the average giallo protagonists, though. Early slasher films tended to have likeable characters, which made their on-screen demises all the more harrowing. (There were a fair share of assholes, of course, but they were recognisably flawed and human characters). Gradually, a slightly-unnerving shift occurred, with disposable characters offered up to be sliced and diced for our viewing pleasure. These characters became so obnoxious and annoying that the audience seemed to be encouraged to cheer their deaths. Body Terror's young characters largely, whether by accident or design, fall into this category, with the inane dialogue, bad dubbing and extreme dickheaded behaviour making them a singularly unlikeable bunch.
Gialli often feature unlikeable protagonists as well, but the best examples of the genre offer up enough other delights to more than compensate for this. There are investigations, set-pieces, fashions, locations etc to massage the senses, and it's simply unimportant whether or not we like the characters. The youth of Body Count's characters probably counts against them too-without wanting to come across like an old man waving his fist at the weather, teens are generally louder and more vapid, with the calming effect of age usually making their behaviour more palatable. David Hess, who effectively plays a thuggish madman for the entire running time, is far more pleasurable to watch than any of the kids. So, evil or insanity is fine; constant shit jokes about dicks are not.
The killer's motivation, a past trauma straight out of the Freud-via-Argento school, is typical of both gialli and slashers. This is one of the several ways in which certain slashers took their lead from gialli. Each of the three above examples of slashers with masked human killers has a similar past incident as a root cause. Gialli didn't invent such a motive, of course (Psycho would probably be the most famous, and influential, such film), but it's interesting to follow the move from Italy to America, and back to Italy (with the supernatural disguise adopted by the killer here being as American as you can get).
That four writers are credited (including the great Dardano Sacchetti, under a pseudonym) boggles the mind-the plot is paper thin, the murder-mystery aspect woefully undercooked, and the dialogue is painful. It's not completely without redeeming features, however: the aforementioned Hess and Farmer are always watchable, as is Charles Napier as a grizzled sheriff who seems to spend most of his time standing and staring at things. John Steiner and Ivan Rassimov also pop up, each trying to outdo the other for the coveted title of Least Important Role Ever (although they are potential suspects for the murders). The score (by Claudio Simonetti) is cheesy and fun, and there's an excellent dream sequence. This sequence isn't shot with any great flair, in common with the rest of the film, but its design and editing are terrific.
The film's ending, in which another, seemingly real shaman appears after the killer has been apprehended, is a classic throwaway slasher ending, too. Think Nightmare on Elm Street, Friday the 13th etc-logic gives way entirely in service of a shock (albeit not a very shocking shock in Body Count's case; we watch a character see something and become frightened, before a straight reverse shot eventually shows what the something is). Italian films had long traded in illogic and strange endings, but they usually had an underlying ambiguity. One could argue that the alleged existence of an actual shaman imbues Body Count with a similarly ambiguous air, but it doesn't really-it's just a cheap, disposable way to end a cheap, disposable film.
*Another good pun here; they often take place at campsites, eg The Burning, Friday the 13th, Sleepaway Camp. Not to mention Body Count.