Like Frank J. Fleming, whom I follow on Twitter, I did like this, from Nicholas Kaufmann:
My apologies to the Goodreads reviewer who found my novel about vampires on a submarine “unrealistic.”
Yes. When writing about vampires, it’s important to write realistically. Most of us have not encountered any vampires in the course of our lives, and we might get the wrong idea about them.
It should go without saying but I will say it anyway. Any comments from commenters who have had direct experience of vampires would be particularly welcome.
No idea what Nicholas Kaufmann’s novel is like, but often what people are complaining about when they say things like that is lack of consistency. Such as if you establish rules about what vampires can do and then break them. Or perhaps the complainer was a submariner.
One of the standard ways of writing hard Science Fiction is to change one thing from the real universe. One invention is created that does not exist in the real universe, or one technology is made possible. Given that, everything else must remain as in the real universe and everything must be consistent. One of the tests of the quality of sf of this type is just how rigorous is the correctness and consistency, and dare I say it the realism, of everything else.