The horrors of the story are in the fact so many horrifying things are left just barely explained, just enough to let you imagine something terrifying. By the end, you have more questions than answers, but I did not think this was unsatisfying. It makes you more interested, with a stronger desire to pick up the next book and see what happens next, what gets explained next.
The biologist was also an extremely endearing character, to me at least. She was a very flawed person, but very human, very relatable. There's no way to pin her personality or character down to one or two words to represent traits. She is the biologist, and there is so much to her.
I started the second book today and it looks like I'm going to get a lot of answers (there was actually a major revelation in the first few pages in regards to a major character from the first book and I loved it.) While I expect that the scrubbing away of the mysteries won't be 100% satisfying, may take away some of the fun of the first story, I'm still eager to read.
I'm also very excited at seeing people tag this series with "LGBT characters!" I was kind of tired that the heroine in the first book