Bug is not to be confused as a remake of Jeannot Szwarc's 1975 film of the same title also very obviously about the same subject. No, this is William Friedkin's film adaptation of Tracy Lett's play of the same title. There is obviously no confusion over who William Friedkin is-- the same Friedkin who brought such extreme depictions of human ugliness and their extreme leaps and bounds in 1973's The Exorcist, 1971's The French Connection, 1985's To Live and Die in L.A., and 2003's The Hunted. Unlike Szwarc's Bug which is about actual bugs that destroy an entire town and a man's obsession over controlling them, this bug is a psychological one.
Just like the play (which this reviewer had the great pleasure of seeing performed on stage), the film tracks the life of an extremely lonely woman (fantastically played by the ever brilliant and beautiful Ashley Judd) who encounters a rather odd but understandably vulnerable man played by stage actor Michael Shannon (who originated the role when it was first performed on stage). Harry Connick, Jr gives an impressively scary performance as Judd's ex-husband who has come back to collect from her. The real question later becomes whether Connick's character is a detriment or help to battling her character's secret. Like all Friedkin's movies, the film is enveloped in cold blue tones and viewed through a documentarian's handheld camera. One of his major contributions to cinema is his very influential use of handheld photography and his ability to make us cringe at the sight of very realistically depicted violence. When it comes to showing us the razor's edge of madness, this director does not hold back ("those people get you in the teeth!").
Like Friedkin's The Exorcist, the movie establishes a great deal of reality and normalcy before the horror starts and like Friedkin's horror masterpiece-- the movie bores into your psyche. However unlike The Exorcist, these things that are driving these characters to believe anything and everything is infesting their entire motel room and their bodies are never seen. In the end, what is really scary is how far these two characters will go to comfort each other and to stay together to fight imaginary bugs. Of course as far as these characters believe, they are doing the world a public service by destroying these "experimental" bugs. Sounds like William Friedkin in spades to me.