Very imaginative vintage sci-fi. Mysterious Island is vintage in a double sense: because of the 1961 release date, and because of the much earlier 19th century Jules Verne story that the film is based on. Unusually for a mutant-monster movie, the plot is fairly complex; the balloon ride itself has enough potential interest for a movie. Since sci-fi is intrinsically futuristic, it’s always fascinating to see how technology is treated–in this case from the vantage point of Verne’s 1874 publication date (though it’s set in 1865).
As others have noted, Mysterious Island is also an adventure story. Color is used to good advantage, with the exotic (largely faked) flora, fauna, and topography. The giant crab sequence is very realistic; I don’t see how CGI can improve on this, other than to make a creature look absurdly hideous. The giant bird (exotic chicken) manages to be both dangerous and funny–a nice touch. The giant bees and the octopus, like the crab, look and behave very naturally.
Since the characters aren’t in constant danger, the moments of levity make sense; after all, these guys have all escaped from war. Also, the sense of discovery maintains suspension of disbelief–random events (weird creatures, caves, volcanoes, other stranded folks, pirates, etc.) might be expected in an unknown world. Logically, the characters plan an escape, meanwhile settling in to a sort of organized domesticity. Unfortunately, there’s a bit too much of that; every little thing is not only shown, but painstakingly explained as well.
What really elevates Mysterious Island is Captain Nemo. As a counterpoint, if not quite an antagonist, he lifts the story out of mere adventure into something more dramatic. In the best storytelling tradition, the plot builds as it progresses. Interest is sustained by adding elements. The transitions are well-handled; the balloon naturally leads to the island, discoveries there lead eventually to the semi-mythological Nemo; the pirates appear as Nemo’s ship is discovered. (And what a ship! A Victorian combination of opulent interior of brass, wood, and velour, and a menacing exterior–with period-correct riveted armor plate).
As soon as Nemo has dispatched the pirates and explains about the coming apocalypse, there’s a kaleidoscope of action and exotic imagery. The volcano erupts, an Atlantis-like sunken city appears, as well as the giant octopus, Nemo’s ray-gun like “electric gun” deals with it, and, thanks to a fairly ingenious plan, the ultimately successful escape. The balloon, in which the adventure began, has a part in completing it. That’s enough doodads and derring-do for a couple of movies.
Most of the performances are strong enough to carry the plot, although the women’s roles are about as skimpy as Beth Rogan’s outfit. More successfully, the black soldier is as important as any of the other guys, and is treated no differently–quite progressive for 1961. Mysterious Island, despite some slow stuff, is very entertaining, and not just from a sci-fi perspective. 8/10.