Were it not for the fact that the classic sci-fi feature, “The Invasion of the Body Snatchers,” appeared nearly a decade earlier, this film could have been a noteworthy original alien movie. As is, it would have played better as an episode for Rod Serling’s legendary “Twilight Zone.” More realistic than many Martian monster stories, the aliens here are comparable to electrical charges of energy, intelligent forces that are without physical form yet can assume the shape of earthly beings, becoming non-genetic clones.
Writer Harry Spalding does an admirable job with story and script. The ending is effective and keeps within the plot framework. Most of the action takes place in one locale. So Spalding had to write for a restrictive setting. With less skill behind the pen, the movie would have played as a stage drama. Director Maury Dexter met the challenge well, for the show moves along at a fast pace.
The acting is first rate. Kent Taylor, TV’s “Boston Blackie,” was originally groomed by Hollywood to be a major romantic lead, but he never quite made the big time. He ended up making many B features during his long movie career. Yet he was an able actor who could be counted on to give a good performance, as he does in “The Day Mars Invaded Earth.” Need I say Marie Windsor was one of the screen’s favorite femmes fatales? She was such a convincing actress that many believed her screen image was the real thing. As with Taylor, Windsor never gave a bad performance. The surprise in this film is William Mims as Dr. Web Spencer who makes the most of his supporting role.