I love 1960s-style martial arts action, and the only thing THE THREE FANTASTIC SUPERMEN lacks is the obligatory "hi-yah!" This amusing comedy combines elements of BATMAN, THE GREEN HORNET, Mexican wrestling movies and spy-capers. Much of the humor might have been funny back in Europe in the 1960s, but it came off as stupid or just plain odd when I watched the movie in America during the 1990s. Maybe they didn't have a budget to really develop the slapstick and satire into something honestly funny, or maybe the English dubbed version simply lost something in the translation.
Nick Jordan is particularly annoying as the mute superhero, a role given to Salvadore Borgese in follow-ups (ironically, Borgese only cameos at the beginning of THE THREE FANTASTIC SUPERMEN, as a bazooka-toting henchman). Jordan's superb acrobatic flips and mini-trampoline stunts really highlight the karate fights and help to elevate them above other martial arts of the period (i.e. THE AVENGERS & WILD WILD WEST). I dare say that as far as 1960s martial arts go, THE THREE FANTASTIC SUPERMEN's spats are second only to THE GREEN HORNET!
I won't go too much into the script; you'll just have to find this rare gem and see it yourself. For now, let's just say that FBI agents get their hands on these bullet-proof 'Superman' (why Marvel never sue'd them is beyond me!) outfits which turn common jewel thieves into acrobatic heroes! Some times our zany heroes are evading cops, some times they're thwarting a mad scientist and his 'human duplicating' machine, and sometimes they're just being silly. They're never boring though (that doesn't happen until the movie's many sequels came along)!