Thanks to an excellent literate script by master Nigel Kneale and intensive, atmospheric direction by the underrated Val Guest (who both scored great marks with "Abominable Snowman"), this ranks as one of the best and most disturbing Science-Fiction Thrillers. I don't need to reiterate the intriguing story, but it builds gripping suspense from the word 'Go' and finally escalates into a crucial state-of-alarm that climaxes in a thrilling and terrifying showdown at the secret alien refinary plant in the remote British country. Pretty violent and grim for its time, and it still retains its entertaining and thought-provoking qualities. The confrontation between the workers and the alien-controlled government & military "zombies" has certain Marxist underlying themes of the 'workers revolt againest the oppressive, dictatorial rulers' - who, in shattering fact, are aliens who are truly alien - and thoroughly malevolent. Some kaffka allegories of corrupt government and fascism are conveyed here in the bleakest of ways. Kneale's intelligent, riveting screenplay also served as the basis for the James Bond plots and wild devices that surfaced a few years later in the rebelliously turbulent 6O's - which this insightfully compelling Science-Fiction Classic seems to sinisterly forecast. Not your typical or campy monster movie by any long shots. Also, quite cynical for its time, as Quatermass is forced to become the angst-ridden, alienated hero (anti-hero) in his accidental uncovering of conspiracy (his plans for a proposed moon project is swiped by them) and cover-ups: Very Hitchcockian. Also sounds a lot like X-FILES, doesn't it? I believe this was XF's producers favorite childhood science-fiction film; the dark, ominous influence and inspiration is undoubtably present. Not a kid's flick by any means. I HIGHLY RECOMMEND this hauntingly memorable and intensely scary classic. Probably the most starkly realistic vision of what a true alien invasion might be like. Genuine nightmares to take to bed - and wonder.