It really makes no sense how this film could not have worked. Working off a script based on a Robert A. Heinlein novel, with the venerable Donald Sutherland in one of the lead roles, and with alien invasion the subject matter, this should have been at least a seven star Science Fiction film. As Sci-Fi goes, the superior ones focus more on futuristic and/or scientific concepts, with action and/or special effects adding to the spectacle. That is why films like the Star Wars saga really aren't Sci-Fi, but action/adventure first (and in the case of Star Wars, fantasy) and science fiction second at best. This film does delve into the biology and culture of the aliens, but just barely. Mostly it focuses on hokey special effects and a few watered-down action scenes to fill up screen time. The aliens themselves are quite realistic and original, a plus for the film. The chemistry between Donald Sutherland as the leader of a secret government agency and his son, played by Eric Thal (an unknown at the time) is actually quite good. In addition, Julie Warner actually does well as the scientist working for Sutherland and of course plays the romantic interest for Sutherland's son. While not a superior actress, she performs adequately, although her talents are more suited to television, as it appears this movie was. While most will think, as I did, while reading the plot synopsis of the film that it is a rip-off of "Invasion of the Body Snatchers" (Sutherland starred in the remake of this film in 1978), the actual book was published in 1951, prior to the original film as well as the novel written by Jack Finney. Bottom line: not a bad movie to watch when you know you will be distracted as it requires very little of your attention and there are enough action scenes to move the pace along, but science fiction and Heinlein fans will be disappointed.