I gave this anime 9/10 and i think it deserves much more then other people gave that anime only because they score high only the "mainstream". In my opinion anime have really interesting plot and its good variation about "vampires". Yes bloodivores are basically more science related vampires. Anime is based on Chinese manhwa and i dint read it so i cant and i will not score this anime based on how "true" it is to it paper original. Story is great trust me only sad thing is it doesn't advance that much and ends in "cliffhanger" so the second season maybe will be made. Animationis really god but its not beast I've seen, would be great if characters and background would have more details. And if we speak about characters they are really good, maybe not so awesome deep but they have they story and secrets.
Sound and music in this anime is medicore, dont get me wrong its not annoying its just not getting "into ear".
I really enjoyed this anime and i think its one of better anime in last season so just try.