The Colossus movie scenario is sort of a combination of "War Games" in the sense of getting out of hand and the novel "This Perfect Day" in which all of society is regulated.
The use of good, but not over the top, actors gave an eerie feeling of reality to this film.
It is 1966 with the complexities of nuclear war we must turn to artificial intelligence to handle the multitude of factors in a reasonable time. We must keep in mind that this computer "Colossus" (named after the real life machine by Turing) can only do our bidding. What is this? Colossus has discovered another entity in Russia (Guardian), and requests to converse with it. Well we can always pull the plug (yeah sure.) To counter the threat of being socially separated the computers threaten to launch nuclear missiles. At the U.S. and Russia. Getting increasingly pushier Colossus, after requesting voice recognition and voice synthesis (a spooky sixties version of voice synthesis), goes on to regulate the lives of the people who created it; of course it is for their own good.
One can put up with nuclear war if need be, but regulating lives is intolerable. Something must be done. Watch and see what unique solutions are planned. Will they succeed? Who are you rooting for?