The trailer seems promising as much as the storyline, but overall not that great.
The story is linear yes, but lacks a lot of background history that would help to understand the drama way better (like, why do these people even exist??? where's the point of this story???). A special mention goes for the special effects, can't say anything bad about them, honestly really splatter and were well made, beyond my expectations to be honest!
Does it need a second season? For me yes, many plot holes are left without and answer in the end!