The film depicts the personal and professional crises a writer experiences after a series of encounters with non-human beings.
The film strongly benefits from the performances of Christopher Walken and Lindsay Crouse. Walken (always engaging) manages the challenging task of making Whitley Strieber a compelling character; you care about him even if you don't necessarily like him 100% of the time. Crouse succeeds as Whitley's wife; the two together are immediately believable as a married couple.
The film is arguably the most intelligent film about the alien abduction/ visitor phenomenon. Unlike countless cheap, made-for-TV films, where the emphasis is on the sensationalistic, "shocking" aspects of the subject, COMMUNION focuses on the psychological and emotional harm the experience does. We see Strieber describe his experiences to his medical doctor, and then to a psychiatrist. Once his own mental health has been established, then (and only then) does he begin to consider the possibility that the creatures he has seen are actually real.
After questioning everyone from medical professionals to fellow abductees, Whitley realizes the only ones with the answers are the visitors themselves. At the film's climax, he willingly presents himself to the visitors. This is what makes COMMUNION transcend every other film about the phenomenon.
Director Phillipe Mora successfully creates a "you-are-there" atmosphere, letting the actors improvise a lot of their dialogue. There are two distinct moods: one, where things are brightly lit, secure, and normal; and secondly, the dark, unsettling world Strieber inhabits only with himself and with the visitors. Mora's direction is subtle, with cues in both the dialogue and a detailed, occasionally wry visual style.
Another plus is Eric Clapton's opening and closing theme music.