When I first saw this film, it was playing in theaters. It was the first 3D film I saw that I knew would simply not have worked in 2D. My original review concentrated on the content of the film, and its portrayal of the art work. I decided to rewrite my review to address the Blu-ray 3D release itself. How much you will enjoy this still has to do with how likely you would be to watch a documentary about caves in the first place.After owning a 3D HDTV for about a year, I now have my second 3D title. The first one came with the TV. It's not that I dislike 3D, but 3D offerings have been scant, overpriced, or simply for titles that I didn't think were worth owning or didn't benefit enough from 3D to warrant a purchase. In this case, I knew before the Blu-ray disc was released that I wanted to own it as soon as it came out. Overall, I'm not disappointed.The film still stands on its merits. The presentation, however, comes with a few artifacts that were not present in the theatrical release. One recent review I read was from a viewer who questioned whether it was even shot in 3D. For the most part, I think the 3D presentation on the Blu-ray disc held up to my expectations. But there were a few places where pieces of the background shifted to the foreground in a very distracting way. Overall, I stand by my belief that this film simply would not work in 2D. All you need to do is close one eye while watching some of the scenes, and you will see how you completely lose a sense of how the cave and the art go together.When I watched the film in a theater, I wondered early on how well it would hold up for the length of a feature film, given the number of items that were presented. As with a visit to a museum, pacing is important. In a museum, you have the advantage that you can spend as little or as much time as you want looking at any given work of art. For that reason, it was important for the film maker to show multiple perspectives of many of the same areas. Although a disc version gives the added advantage of a pause button, it's also a matter of lighting, angle, and other factors that go into your ability to appreciate each drawing.Aside from the film itself, the only special feature is a "documentary" about the music made for the documentary. It's mostly just footage of the composer and musicians putting together various parts of the score, but somewhere in the middle it does go into the composer's five string cello with a low F string, and how it came to be. Documentaries assume a certain specific audience to begin with, and this will appeal to a limited overlapping subset.Overall, I'm still glad I bought this. Subsequent viewings made me less forgiving of some of the excesses of the narration and its philosophical ramblings, but you need to watch this for the subject matter and overlook those. While the 3D transfer might not have lived up to what the theatrical release offered, I can't say that it was enough of a problem to change my overall view. As annoyances go, I'd rather have them fix the parts that force me to watch previews and prohibit me from getting to the menu. The documentary was made under less than ideal conditions, with limited access to the cave, with limited room to film. Considering the constraints that the cinematographers had, I'm amazed at how much this film has to offer.