The world of Nyx seems artificially constrained in a way that makes it feel like it's fake. Sauma spends no time explaining the science at all, just says one gets there through a wormhole and briefly describes what it looks like. It's all about what Iris goes through. The participants are weirdly cut off--they can (and are required to) post about their lives on social media, but they are not allowed contact with Earth and so never get feedback on what they are doing.
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The writing is excellent and I feel like I understand Iris. It's not a book to lift your spirits but it's worthwhile.