it really make no sense how this film could not have work . work off a script base on a robert a. heinlein novel and with the venerable donald sutherland in one of the lead role and and with alien invasion the subject matter and this should have be at least a seven star science fiction film . a sci fi go and the superior one focus more on futuristic and or or scientific concept and with action and or or special effect add to the spectacle . that be why film like the star war saga really aren not sci fi and but action or adventure first ( and in the case of star war and fantasy ) and science fiction second at best . this film do delve into the biology and culture of the alien and but just barely . mostly it focus on hokey special effect and a few water down action scene to fill up screen time . the aliens themselves be quite realistic and original and a plus for the film . the chemistry between donald sutherland a the leader of a secret government agency and his son and play by eric thal ( an unknown at the time ) be actually quite good . in addition and julie warner actually do well a the scientist work for sutherland and of course play the romantic interest for sutherland son . while not a superior actress and she perform adequately and although her talent be more suited to television and a it appear this movie be . while most will think and a i do and while read the plot synopsis of the film that it be a rip off of invasion of the body snatcher ( sutherland star in the remake of this film in 1978 ) and the actual book be publish in 1951 and prior to the original film as well a the novel write by jack finney . bottom line represent not a bad movie to watch when you know you will be distract a it require very little of your attention and there be enough action scene to move the pace along and but science fiction and heinlein fan will be disappoint .