It's okay. I won't be watching it again. It's about as recommendable as Season 1, i.e. don't bother unless you're specifically looking for horror, but it's decent enough.
Season 1 was an anthology show that grew a plot. Season 2 has a clear storyline all the way through, with only mildly anthological touches. The hero last time was Sousuke Banba (monster researcher, black suit) and the villain was Masaki Kimura (monster researcher, white suit). They've both returned. I could have sworn one of those was getting killed last time I saw him, but it seems he's got better.
Season 2's big development is that the baddies have realised that kagewani blood can infect animals and people. One drop can turn you into another kagewani, or worse. That's how they breed. This means that a traumatised little girl might also be the demon that's killed her entire village and so she's about to try to eat Monster-Slaying Girl too. There's nothing unusual about the twist of a small girl being a demon, obviously, but what makes it particularly horrible here is the fact that until recently she'd have just been been a normal girl. Thinking about it, her metamorphosis and the ensuing deaths (including all her family) were probably caused by the monster-researching corporation deliberately infecting her with kagewani blood.
As always with unstoppable killing machines in genre fiction, the response of evil scientists is to try to weaponise them. Yeah, that's a good plan. Lock yourself in a lab with a kagewani and see what happens. Somehow I don't imagine weapons research is quite that suicidal in the real world. This season has a particularly impressive twist on the cliche, with Honma planning to exploit the kagewani blood in war by turning the enemy into indestructible supernatural monsters. I spy a potential flaw in this.
Banba's more interesting than last time and a lot more dangerous. Kimura's straddling the boundary of hero and villain. Honma's way over that line. Monster-Slaying Girl (aka. Nagi Yaguru) has sympathetic motivations, but a "take no prisoners" attitude and no interest in playing nicely with the rest of the cast.
The elephant in the room, as always, is the animation. It's dog-ugly. It's photos under a bad Photoshop filter, stretched around in 2D by an eight-year-old with Adobe Flash. (I might be exaggerating. He might be nine.) This looks bad in normal scenes, really bad when there's a human on-screen and hilariously bad during action. Personally I can forgive it because the show's horror and so it's appropriate to have some ugly, disorientating anti-realism, but that doesn't make it good to look at. That said, though, some episodes do better than others. The kagewani themselves look eerie and work well in this style, being shadows that swim across the floor in two dimensions and kill you. Thus the last three episodes look pretty good, with Nagi Yaguru's kagewani fight looking downright impressive compared with her action scenes on debut in ep.5.
If you don't worry about visuals, though, the show's fine. You could do worse, although you'd probably delete the files afterwards and never give it another thought. It has some nasty ideas, e.g. the snake with a paralysing gaze that then takes its sweet time in slowly slithering up in front of you and eating you. I also enjoyed "he was wounded in an accident!" (If by "accident" you mean "locking the door on him and then watching his fate through the security window".) I still wouldn't recommend it except to horror fans, but so far I've still watched 26 episodes of it and I'd watch a third season.