It's a documentary in the mold of the mondo films or Faces of Death, and the film mostly consists of archival footage, but some of it appears to have been shot by a cameraman specifically for the film (The Kennedy assassination zoom in shots on the window and tracking shot inside the interior where Oswald fired and the man demonstrating Whitman's behavior appeared as if they might have been made just for this film, as well as some of the earlier footage). Obviously don't watch it if you're unwilling to see violent and gruesome images. Often it just discusses the material and has little graphic material to show, but they don't shy away from people being shot on screen and even a few suicide or after death photos.
The beginning was the most interesting part because all of the footage was just everyday violent scenes and showcased the gritty streets of the most dangerous American cities. It seemed initially like it had an underlying message and was more artfully directed than something like FoD. Quite a depressing atmosphere to the whole thing, but then all of the iconic scenes of successful or attempted assassinations of famous figures (Wallace, Reagan, MLK, JFK, and his brother Robert), followed by a few mass shootings/snipers, serial killers, Jonestown, etc. occurred--some more obscure than others. Though it's interesting if you haven't seen a lot of this footage, it does become a bit rote, especially if you're familiar with any of the content. I'd already seen the footage from Bundy and Kemper, and a few others--unfortunately, most of the archival footage is not edited together in a unique way and has rather banal commentary.
Aside from some occasionally inventive editing and the strong start, and some decent music choices, most of the footage is available on Youtube, and this is only of note as a clip compilation film with little direction other than to document a bunch of violent scenarios, usually by category rather than chronologically. It offers no real insight into the American condition, why the violence occurs, or how to ameliorate it, and very few statistics (all shoehorned in at the beginning). It's also wrong at a few points--average IQ for murderers of the type presented tend to be below 100, but the more charming and higher IQ killers usually get all the media attention (Might have been flimsy data at the time, but I'm just pointing that out). As well as the odd suggestion that people in prison for life or with a long sentence would be released because of prison overpopulation or something (They presumed Sirhan Sirhan would be released just 3-4 years after the film debuted in '81). Absolutely no documented information is included to substantiate any of these claims or even any concrete examples are given (they could have at least interviewed a few cops or legislators or something).
The ending with Lennon's peace vigils is rather tepid, but it seems they were pressured to end on a more positive note.
A quick listing of footage or details in the film: Wallace, Lennon, Reagan, MLK, JFK, and his brother Robert (there are also Sirhan Sirhan interviews), all either successfully or unsuccessfully assassinated; Ted Bundy, Edmund Kemper, Wayne Henlon and Dean Corll, Brenda Spencer, John Wayne Gacy, Mark Essex (and two others), Charles Whitman, Jonestown Massacre, Tony Kiritsis, Manson Family, Robert Smith, James Hoskins, and some very brief footage of the Vietnam War. There's some other content, but that's the bulk of it.
