One of the outstanding features of this movie can be summed up in a single word: electronics.
Released in 1955, "This Island Earth" is one of those rare sci-fi movies that embraces the new electronics revolution that was looming in the mid-50's, heralding the transition from mechanical devices and controls.
The movie is still up on YouTube so save a copy or watch online. Be sure not to miss the appearance of Russell "The Professor" Johnson, in one of his many roles before his run with "Gilligan's Island" in 1964.