This is not a great movie, but it is an enjoyable one. It's the kind of movie that's very easy to underestimate. The kind of movie that sort of sneaks up on you by being good in unexpected ways.
It's also a film with a fair bit to interest movie history buffs [feel free to skip the next three paragraphs if you have no interest in this kind of stuff - oh, and thank you to the IMDb, which formed the basis for much of my research]. The female lead is played by Faith Domergue, who apparently got her start in movies largely as a result of being Howard Hughes' mistress - from the age of fifteen. On a note that is perhaps then ironic, but certainly less disturbing, her character in this film is actually portrayed as a highly accomplished scientist in her own right. She's hardly a protagonist of stature equal to the male lead, and yes, she does do her share of screaming, but she is there on her own merit. She doesn't get to be where the action is just because she's someone's daughter or nice or wife; unlike so many other female characters from the science fiction of the day.
To me, the most interesting thing about the male lead actor is that "Rex Reason" is actually his real name: the one he was born with. Seriously, who could have come up with anything better for an atomic age science fiction star? He seems to have enjoyed quite a successful career as a character actor and B-movie lead, and is still alive and kicking today at the age of 81.
And finally of course we come to Jeff Morrow. While not playing what would normally be considered the leading man of the piece, he does get top billing. He is also generally accepted as having given the most compelling performance of the movie. By contrast with "Rex Reason", "Jeff Morrow" is actually a stage name. Morrow's real first name was Irving. Popularly known as "the Cro-Magnon man" for his unusually large brow (even without the pretty spectacular makeup he wears in This Island Earth), like Rex Reason Morrow had a fairly successful career as an A movie supporting player and a B movie lead. Aside from his own starring role in This Island Earth, Morrow is perhaps best known for playing a Roman centurion in The Robe
: a rather dubious Biblical epic starring Richard Burton. Curiously, that movie also featured another major science fiction cult actor, Michael Rennie, who is of course today most famous for The Day the Earth Stood Still
Well, so much for the history. Now back to the movie.
Many will know this film best for being lampooned on Mystery Science Theatre 3000. In truth, that's not a fate it deserves. Yes, it is a "B" movie, but only in the way that virtually all science fiction films of this era were B movies. That remained the case right up to the time of Kubrick's groundbreaking 2001 - A Space Odyssey
. But B movie or nay, This Island Earth is still a long way from being schlock.
That said, this is a movie that a nine or ten year old could not only watch and enjoy, but would also "get" completely without missing any extra layers of meaning. If such unsophisticated fare doesn't sound particularly appealing, I'd be quick to add that this is a movie that most adult sci-fi fans should also enjoy immensely - provided, that is, that they're not a complete bunch of old sourpusses.
So if you're looking for intelligent sci-fi, look elsewhere. This is not a movie that deals much in ideas. Equally well, if you're looking for hard sci-fi, again look elsewhere. The "science" in this movie is almost pure bunkum. The sole exception to this is that unlike so many other works of science fiction, this is a movie that understands that energy is a finite resource, and that interstellar space flight would in fact require and consume that resource in abundance.
So if we don't get hard sci-fi and we don't get intelligent sci-fi, what are we left with? Quite simply a tightly scripted and generally well put together action-adventure story, with acting that's both engaging and appropriate to the material at hand.
But most of all we get a movie that's an enormous amount of fun just to look at and listen to. The special effects are amazingly good by the standards of the day, and hold up pretty well even now. But more than this, the sets, the costumes, and the general feel of the piece give us a real tour de force of the language of 1950s science fiction, and of 1950s futurism more generally. This is serious classic sci-fi, complete with flying saucers, bug eyed monsters, and ray guns. Plus lots and lots of stylized atom designs liberally scattered around for no apparent reason.
All this and a soundtrack that even includes a theremin.
What more could any classic sci-fi fan ask?