Cast and Crew: Ishiro Honda (Director), Takeshi Kimura (Writer); Arthur Rankin Jr., Tomoyuki Tanaka (Producers); Akira Ifukube (Score); Eiji Tsuburaya (Effects); Paul Frees (Dr. Who, English version),
What It’s About: A trio of UN research scientists-Carl Nelson (Rhodes Reason), Jiro Nomura (Akira Takarada) and Susan Watson (Linda Miller)-visit Mondo Island to get a look at King Kong while their sub is making repairs nearby, which allows Kong to do his Kong thing (saving a beautiful blonde from a series of prehistoric monsters). Meanwhile, Dr. Who (Eisei Amamoto) builds a Mecha-Kong to provide secret agent Madame X (Mie Hama) with a very powerful, rare and nearly impossible to mine radioactive element. There’s just one problem: Mecha-Kong is short circuited by the radiation. The obvious solution? Kidnap King Kong and force him to dig, under the power of hypnosis. When that fails, only beauty can force the beast to work for Dr. Who, so he kidnaps Susan, Jiro and Carl, who turn out to be (surprise, surprise) unwilling to tell Kong to dig for Dr. Who. When Kong busts out of Who’s arctic base and heads for Tokyo, Who follows, hoping to use Mecha-Kong to recapture the King. Will Tokyo survive yet another Kaiju throw-down?
Why Watch it Today?: When the original King Kong was released on this date in 1933, no one could predict that in less than 40 years he’d appear in a Japanese-American co-production/cartoon tie-in as a superhero battling a Chinese communist plots to control the world, but that’s just what happened in this Toho-Rankin/Bass mash-up of the Kaiju and spy genres.
Other Choices: King Kong Vs. Godzilla, Mighty Joe Young, A*P*E, Yeti
The League of Dead Films 
Now, this sounds absolutely fascinating. Yet, I suspect it might be painful to watch all the way through. Are there other Mecha great-apes? I find the notion both enchanting and appalling.
I believe this is the only Mecha-Ape movie. It drags a little in parts but is pretty damned entertaining overall. I guess partly your enjoyment will depend on how much you like these kind of things.
I just like to imagine the narrative negotiation.
“Ok, here’s the plan: King Kong vs. Godzilla”.
“Again?”
“Right. We need something else. Um…”
“Mecha-Godzilla?”
“No. Too many lizards.”
“Mecha King Kong. No one’s done that before”
“Perfect.”
Heh. Mecha-Kong came first, actually, and the crazy thing about this is that it was originally started as a tie-in to a cartoon from Rankin Bass, of Christmas Special fame. The show it tied in with (barely, apparently) exists but I’ve never seen it.
Although your conversation still works, amazingly, since this was sort of a follow-up to KK vs. Godzilla, though they also wanted to do one with KK meeting Mothra and fighting Chinese terrorists and a giant lobster in the South Seas-but more about that one VERY soon. 😉
Oops-that turned into Godzilla vs. the Sea Monster, which was the Movie of the Day a few weeks ago!