According to cinematographer Peter Zeitlinger in his talk at the Berlinale Talents 2015, the first 20 minutes of the film are shot with two GoPro Hero cameras taped side-to-side (one upside down),
because at the time of shooting no 3D-system small enough for the cave shoot was available. The rest of the film was shot on professional, higher-quality 2k 3D-cameras with follow-focus, when they later became available.
The highest-grossing independently released documentary of the year 2011 in the USA.