Project X is a top-secret government undertaking involving trained chimpanzees. Grounded pilot Matthew Broderick, assigned to teach the chimps how to operate a flight simulator, discovers that his charges are to be subjected to high levels of radiation to test potential human endurance. Risking a court martial, Broderick links up with Helen Hunt, the researcher who has taught the chimps sign language, to save the simians from destruction. The serious subtext of Project X is forgotten during a Disneyesque comic finale, wherein the lovable chimps nearly trigger a nuclear meltdown! Without taking anything away from human stars Matthew Broderick and Helen Hunt, we must note that the most engaging performance in Project X is delivered by Willie the Chimp, who essays the challenging role of Virgil the Chimp.
~ Hal Erickson, All Movie Guide