Some of the themes that emerged for me: Minimizing use of natural resources in order to maximize the full capacity of human intelligence.
The role of ritual as a focuser of intent that enables utter, literal transformation.
Profound understanding of other forms of life via literal experience of what they have lived (in this case, using that species' human interaction as an entry point for understanding).
Civilized human society's penchant for consuming nature to benefit materially while suppressing our (well documented) ability to shift shape as a means of enriching our intelligence immeasurably.
I noticed how my mind didn't even question the industrialized hierarchy presented in the film, the ritual of common human toil or even the pageantry that has traditionally accompanied industrial "progress." But I had to struggle with the ritual that became the vehicle of transformation for the two main characters.
What seemed like an unnatural act turned out to be only the human part of what is encountered by the species our hero and heroine sought to be. Their yearning to BE and experience that species seemed very natural.