I don't understand the hype. My main gripes with this book:
- The characters are one-dimensional
- The constant snark is off-putting, especially in the Audible version of this book.
- It was obvious that Grace should be the one to go. His refusal to go willingly was unbelievable. Sure, he did not want to die, but the prospect of a failed mission should have been just as dreadful.
- The mission was about studying Astrophage – why wasn't there an option to at least try to refuel? Astophage has a doubling time of 8 days, so there would be twice as much fuel available if they'd went a week later. It makes no sense to not make it into a round trip. It seems as if the writer created a forced plot point to make it a suicide mission to add some drama, to make it believable for Grace to not want to go. Still failed to make that believable, which pretty much ruins the character. He only remembers his initial unwillingness late in the mission, whereas he previously considered himself to be such a good human being for doing the mission. Wow, conflict! A potential for internal struggle! But it's not being put to use. It doesn't seem to weigh into his decision not to return home (he apparently does not feel shame, because he thinks he will be regarded as a hero).
- I found the speed with which Grace and Rocky learned to communicate by simply pointing at things and recording 1:1 translations of words and taking it from there within a day to be insultingly unbelievable, right from the start up to the point where Rocky effortlessly incorporates sarcasm and irony.
- There were also many missed opportunities. Look, when you're on a mission trying to defend your solar system from an invasive alien species that is on the verge of wiping out humanity, and you encounter another alien life form that is intelligent, breathes ammonia, looks like a giant spider with amazing engineering prowess, superior mental abilities and capable of interstellar flight, and the spider wants you to point out the exact location of your home planet on a model of your part of the galaxy, maybe you should have second thoughts about this? That would be not only believable, but trust issues would create much-needed tension and drama. Grace and Rocky hit it off from the start, are always kind and understanding and just work out a bunch of engineering challenges until they accomplish their goals. That was just boring.
- Everything about language, history and the nature of intelligence was unscientific and ill-informed. It utilizes an anthropocentric, essentialist conceptualization of 'intelligence' that betrays a misunderstanding of intelligence and natural selection. The whole tangent about intelligence being a function of the amount of gravity was utterly nonsensical.

That's why I'm only awarding two stars. The story lacked drama, the characters were one-dimensional and lacked development, the writing was bad; but the one quality that could have been redeemable – the science – was bad itself, which also made the rest worse. It's just a bad book.