I have very mixed feelings about this book. I supported it on Kickstarter and maybe expected something else than the authors intended. I would expect some more detailed accounts from fictious biology, something like the documentaries The Future is Wild or Alien Planet or the book After Man. The book has some nice ideas, but basically for every nice idea there is something that made me dissatisfied.
Fully anthropomorphic wasps lacked evolutionary reasoning as opposed to interesting carnivorous fungi. The presentation of Sirens with lousy explanations of their evolution and looking more like some anime fantasy was contrasted with an interesting exploration of crazy ideas about centaur-like creatures. And the last "species", which was just an image of orangutans in a sci-fi setting, was really lazy and unimaginative speculative biology.
In general, I hope the project catches on and convinces some better biology-freaks to join in, otherwise I would recommend you to just read or look through any monster manual available to your favorite RPG game, you basically get the same level of "speculative biology".
This reads a bit like an encyclopedia or a wiki and so while not all of the ideas in this quite hit for me, at the very least each one offers an idea for the imagination to chew on further if you're so inclined. Since many different authors contributed, the styles of each creature entry are quite different in terms of subject, tone, and art and they're all quite short which can be seen as a good or bad thing. Overall I really like the bite-sized speculative fiction format and I'm planning to eventually read the other zines in the series.