This is a documentary that covers from the Big Bang through the evolution and life cycles of complex animals. That alone wouldn't make Genesis very unique--there are tens of documentaries, most made for television, which cover all or some of the same material.
However, one of the unique aspects of Genesis is that it features "narration" by Sotigui Kouyaté, a veteran West African actor. Kouyaté appears on camera often, in a part that seems halfway between a dramatic monologue and the traditional hosting of such documentaries, usually by academics of some stripe. The text that Kouyaté reads, which was written by directors Claude Nuridsany and Marie Pérennou, is much more poetic and philosophical than the narration that normally accompanies this type of documentary. That has benefits, and Kouyaté tends to come across as a less manic human counterpart to The Lion King's (1994) Rafiki, but it also has problems if you read the film strictly as a documentary, as a lot of the scientific information and philosophical ideas are either incorrect or not very well thought out.
However, when covering such a wide swathe of existence, you can hardly expect narration to bog down in fine-grained, sometimes controversial points, and as suggested by the Rafiki comparison, I think it's not quite right to read Genesis strictly as a documentary. Nuridsany and Pérennou shoot for and achieve a film that very effectively conveys an intuitive understanding of holistic or panentheistic philosophical and spiritual views and shows how well they can mesh with current scientific understanding.
But aside from the above, and that is important and subtle material, what really gives Genesis an edge and what makes it crucial viewing to anyone with an interest in these kinds of documentaries is the fantastic cinematography. Other than another film from the same team, Microcosmos: Le peuple de l'herbe (1996), I don't think I've ever seen footage of animals shot as well as this, and I've only rarely seen footage of geology and inanimate objects shoot as well as this. The cinematography features amazing close-ups, crisp images, seamless time-lapse photography, impressive footage (you'll often wonder how they could have obtained some of these shots), and often-brilliant editing. At times the film resembles a collage of abstract artwork as much as a documentary, and the editing helps make the holistic/panentheistic view clear.
Long sections of the film are narration-free. Instead, the cinematography is accompanied by music, so at times, Genesis almost resembles the Godfrey Reggio/Philip Glass film Anima Mundi (1992). At least at one point, the music actually sounds Glass-like. The only slightly distracting element of the soundtrack is that Nuridsany and Pérennou decided to add foley sound effects to many scenes. Occasionally they enhance the visuals, but sometimes they're overdone.
