Taking place some 18 years after ESCAPE FROM THE PLANET OF THE APES, this fourth chapter in the consistently entertaining series is another good one that benefits from an extra strong performance in the chimp makeup by Roddy McDowall. The actor now assumes the challenging role of his own son, Caesar; or rather, the now-grown, angry but clever offspring of Zira and Cornelius, who survived his own assassination attempt at the climax of the previous movie.
It's now the year 1991 (no, not the same '91 that we all experienced, but actually an altered version for the "next" time it comes 'round, having been changed by the arrival of Zira and Cornelius and their events of ESCAPE). The world has become different due to a mysterious virus brought back to Earth from the astronauts (maybe Zira & Cornelius themselves from their future?); as a result, dogs and cats have become extinct while apes increase in stature and rate of intelligence and ability to learn. To replace their lost pets, a business called APE MANAGEMENT (which I presume to be a franchise throughout the world) has been established to train gorillas, chimpanzees and orangutans to serve humans in their homes, as waiters, sweepers, bed-makers, and general servants.
Ricardo Montalban is good as a kindly circus owner who brings Caesar into this new environment, but the young chimp must be careful not to reveal that he is actually the notorious talking ape who threatened humanity two decades earlier. Yet, as Caesar becomes increasingly angrier by the acts of bondage he witnesses among his fellow primates, he launches a full-scale riot to overthrow the community and bring humans to their knees. He is motivated by an all-consuming hatred and wages bloody war as the first step, possibly, to world domination on other continents.
And that's just the point - some viewers say that the battle in CONQUEST is on such a relatively small scale that they can't see how the apes would, or could, "take over the world". But if you pay close attention, the vengeful Caesar only considers this encounter "a beginning", not an all-out apocalyptic defeat of all of mankind in one night! It's easy to gradually come down on this series as it goes along, pointing to the obvious lower budgets and so forth, but director J. Lee Thompson does a great job utilizing the futuristic look of the real-life Century City Complex to pull off a feeling of a city out of tomorrow.
I won't deny that more money could have made this film even better (God knows the pull-over ape masks for the extras are certainly obvious), but I feel it's McDowall's energetic and intense performance that elevates this to a higher level than its budget alone would allow. Don Murray as the evil governor is perhaps a little too theatrical, but Severn Darden is quietly contemptible as his more reserved assistant, Kolp (who would return in the next and final chapter of the saga).
Reportedly, preview audiences found the original ending too violent, so McDowall was called in to loop more "humane" lines of dialogue over some non-matching closeups for the movie's official release. It would be great to see a restored version with the actual ending one day**. But even as it stands, CONQUEST OF THE PLANET OF THE APES has more than enough action, humor and drama to make it a winner considering it's a fourth sequel.
**EDITED UPDATE -- In 2008, a Blu-ray Special Edition was released which featured, for the very first time, the "original" version of the movie. It features several gruesome, bloody, and violent moments which were cut out of the Theatrical Version. Also restored was the more downbeat ending. My review stands for either version of CONQUEST, but die-hard fans of the series really owe it to themselves to check out the "Unrated Cut"! *** out of ****