^Interesting, I don't think I've seen that one.
The Day the 60s Died (2015)
An outline of the revolutionary (and very active) anti-war scene in Kent, Ohio - of course, leading up to the Kent State massacre by the National Guard in 1970. It's a PBS doc, which I found very fair and educational, even after doing so much research and digging around the topic over the years. It contains eyewitness accounts, not only from the demonstrators as we're all used to seeing, but also from the other side, from National Guardsmen who were there during the shooting. It really does paint a more multi-dimensional picture of the context of what happened that day, the events leading up to it and the aftermath it created.