An eccentric scientist enlists the aid of a talented young communication analyst to decipher the strange goings on of a colony of ants in the Arizona desert. But when a young female survivor enters the remote compound, tensions run hot as the study begins to out-maneuver its researchers, leading to a dramatic climax which could threaten mankind. Set designer Saul Bass has employed countless photographic tricks and a sophisticated design to an intelligent production that is bountiful with metaphors and suggestion, but ultimately limited in content and action. The result will more than likely be too esoteric (even avant garde) for a typical audience, but equally thought-provoking and rewarding for those with a more creative persuasion.
The nubile Lynne Frederick is a largely reticent muse to the intellectual bi-play, her naivety to the perils they encounter ultimately her sad un-doing, but also witness to a metamorphosis beyond any of their limited (relative to the ants) cognisance. Davenport is relatively quick to deteriorate mentally (and physically due to a poisonous bite that's inflamed his right arm and rendered it useless), Murphy remains focused on finding a common line of communication. The ants transcend the boundaries of human intellect, and toy mercilessly with the researchers, herding them to a frightening prospect, but it has to be said, one that unfolds much too rapidly in the film's closing sequences.
Sharp photography accentuates bleeding colour tones that saturate the dust-bowl landscape and Bass does an impressive job with experimental angles and visual effects. Add to the melting pot detailed, microscopic cinematography tracking the frenetic behaviour of the army of ants, and the overall effect is sensitively rich. The scene in which the frantic Davenport vainly attempts to capture a tiny exponent darting from the pincer grip of his comparatively clumsy fingers, is an absolute cracker -' the proportions in close-up are positioned with precision detail and perfectly convey the futility of their contest with the significantly higher order.
Overall, it's refined, intellectual, vaguely allegorical and generally compelling viewing -' with more substance to the storyline and attention to the all-too-brief climax, "Phase IV" could of (should of) been a minor classic in its own right. But for now, it remains an obscurity, perhaps the only art-house rendition given to a creature feature to date.
Review by Chris. from the Internet Movie Database.