The famous radio broadcast is a version of the H.G. Wells novel that is telescoped into a one-hour format. Since many of the original listeners believed the book was a live report of events as they were taking place, they would have thought that the actions and developments that took weeks or months in the novel were being enormously compressed into a brief time span. Nevertheless, two very obvious similarities with the novel are that 1) the invasion is by beings from another planet and that 2) the aliens use both heat rays and poison gas (in the novel, the latter is described as the "black smoke") to kill humans en masse. These two points are crucial in that they relate to earth's vulnerability and mankind's. Man is not alone, and there are other sentient beings in the universe. More ominously, there is a power that can wipe man out; it uses high tech weaponry we do not have ourselves. Both points are seemingly intended to create a tone of fear and a reaction of hysteria in readers and listeners alike.
Another crucial factor is that in both versions, the aliens are defeated not by man but by their lack of resistance to microorganisms. What does this say about man's own power or lack thereof? Is this a comforting thought, or does it create a tone of deeper vulnerability and panic?