The film was an adaptation of episodes of Rankin/Bass and Toei Animation's The King Kong Show cartoon series. As with King Kong vs. Godzilla, Eiji Tsuburaya served as director of special effects.
An evil genius named Dr. Who has created a robotic version of King Kong named Mechani-Kong in order to dig for a highly radioactive element called "Element X", but the power of it shuts the robot down. Meanwhile, the crew of a submarine investigate the legend of King Kong on Mondo Island and Susan Wattson is attacked by Gorosaurus. However Kong comes to her rescue and kills it by breaking its jaws, before also saving the crew from a giant sea snake, named the Serpent of Mondo Island. Later, Dr. Who kidnaps the real Kong along with the submarine crew and hypnotizes him to dig for Element X. He soon snaps out of it, escapes and swims off to Tokyo. The submarine crew also escape and Mechani-Kong picks up Wattson, who he carries to the top of the Tokyo Tower where he fights the real Kong. Kong wins and destroys the robot, rescues Wattson, kills Dr. Who and swims back to Mondo Island.
The film opened in the United States in June 1968 on a double-bill with the Don Knotts comedy, The Shakiest Gun in the West Contemporary American reviews were mixed. New York Times film critic, Vincent Canby gave it a particularly insulting review, calling Toho's Kong an "Uncle Tom," and commenting, "The Japanese... are all thumbs when it comes to making monster movies like 'King Kong Escapes.' The Toho moviemakers are quite good in building miniature sets, but much of the process photography—matching the miniatures with the full-scale shots—is just bad... the plotting is hopelessly primitive..."
The July 15, 1968 Film Bulletin, however, gave it a more positive review, saying "Grown-ups who like their entertainments on a comic-strip level will find this good fun and the Universal release (made in Japan) has plenty of ballyhoo angles to draw the school-free youngsters in large numbers..."
WATCH THIS TRAILER:
KING KONG ESCAPES (TRAILER)
JAPAN (US RELEASE)