To be an effective thriller, a sci-fi film absolutely must impart to the viewer a sense of --- coldness, either the physical coldness of outer space or other worlds, or the emotional coldness of science.
Cedric Hardwicke's opening narrative in "The War Of The Worlds" is brutally cold, and the added images uninviting. The martian machines, vaguely resembling "legless swans", are both beautiful and terrifying. They move slowly, in a graceful but calculating manner. They warn of their approach with an eerie, unearthly "pinging" sound.
In the scene where the priest walks toward one of the "swans", the aliens do not impulsively open fire. Instead, they wait. The cruel "eye" peers down on the priest, studying him, in a foreboding prelude to his inevitable annihilation.
Other scenes in the first half also convey this needed sense of alien coldness. We can, therefore, forgive the film for its somewhat corny plot.
The film's second half is weaker because the aliens have to compete for screen time with Los Angeles mob scenes, a showy and irksome display of American military hardware, and dry narration of military war tactics. But even in this second half, suspense filters through, as we watch the heartless "swans" eject their heat rays on a helpless Los Angeles.
For sci-fi films made before "2001: A Space Odyssey", "The War Of The Worlds" is one of my three favorites, along with "Robinson Crusoe On Mars" and "Forbidden Planet".