The Sword and Laser discussion

Heliconia Spring seems to me like two different books in one.

On one side, it is a hardcore hard sci-fi, contemplating a very detailed speculation about how a specific astrological structure (a planet orbiting a star orbiting a bigger star) would affect life for its sentient beings, including climate changes, seismic changes, biological adaptations, natural disasters, religion, culture, and so forth.

On the other side, we have a "hard" fantasy book set in the bronze age (at least I think it is a bronze age), with the struggles of a tribe to survive and evolve in a time of great changes.

Both books fit incredibly well one on top of the other. Reminded me of The City & the City

I admit, however, that I was much more hooked by the "first" book than the "second". I lament that the fantasy book gets so much more "screen time" than the sci-fi. My best moments with this this book came not from when I was actually reading it, but when reflecting upon the idea of Heliconia.

You might enjoy the 2 sequels. The part you enjoyed does get explored further. I would guess that the fantasy story in each book would be of a similar ratio as Book 1.

I would agree that Book 1 is either bronze or Iron age ( If comparing it to Earth' s history)
Book 2 is "middle ages", guns are a new technology.
Book 3 is harder to pin down, but I'd guess similar to 19th century Earth.