High-Rise wants to showcase to us how quickly society breaks down, and take a gander at precisely why.
I personally think that's a bit of a simplification, or, if it's accurate to the film, it is a little inaccurate to the novel and Ballard overall. I'd say environment is a huge thing for him, and it's what distinguishes The Drowned World, The Crystal World, and High-Rise.
In the book, at least, I felt that it was explicitly looking at what man-made environments do to our psyche. We are always shaped by our environment, but that shaping is then reshaped consciously and unconsciously, and it's that paradigm which High-Rise is most compelled to peer at. The high-rise itself is very often described as a natural phenomena, e.g. the exterior of the building as a cliff face - man responding to nature, mimicking it because it's all we know, but then that mimicry distorting when it becomes 'ours'/artificial.
If you'll forgive a favourite [non-spoilery] passage from the book:
Laing leaned against the parapet, shivering pleasantly in his sports clothes. He shielded his eyes from the strong air currents that rose off the face of the high-rise. The cluster of auditorium roofs, curving roadway embankments and rectilinear curtain walling formed an intriguing medley of geometries - less a habitable architecture, he reflected, than the unconscious diagram of a mysterious psychic event.
I've not seen the film yet, btw, and I'll probably have to wait for its home release. I was always a little nervy about any adaptation, though, because I just don't see how you can suitably replicate precisely how Ballard went about it. There are quintessential techniques used which can't really be approximated in a film, simply put; if a character in a book walks into a room, we only learn about the room and what's in it, and how it 'feels' courtesy of what the author chooses to tell us. In a film, we see a character walk into a room and the reality of the room is evident.
Cinema is, generally, too often an overly reliable narrator.
On page, High-Rise's true horror barely shows itself until the end, by which time the reader - just like the characters - has been acclimitsed to the mundane normality of it all; we don't really react, because the characters don't. In a film, how can we not see the reality of the escalation? Without very careful filmmaking, the surreal, dislocated psychological horror/non-horror is surely easily undermined.
If High-Rise does have a problem, it's a lack of characters who are in any way relatable.
Well that, at least, is accurate to all the books I've read of his so far (Hello America's up next). I've never read the novel of Crash because I love Cronenberg's film too much, but dispassionate and dislocated characters who aren't really supposed to be identified with - at least in conventional ways - seems to be a running theme.
Going off the rather nifty trailers alone, I'd say Tom Hiddleston's note-perfect for a Ballard lead, so I'm looking forward to his performance.