Read chapter 1 and so far:
1) The main antagonist is evil for the sake of being evil, to reinforce the story's black-and-white morality, which makes the conflict a bit dull, instead of engaging.
2) The teenagers killed in chapter 1 weren't evil at all. They were neither violent, nor sadistic, and genuinely didn't understand that Gijin apparently have emotions, which makes the protagonists look like psychopaths for slaughtering them. I can't root for them after this.
3) World-building is also a bit lacking. "The setting is real life, except with X, and everybody is obsessed with X" is a bit uninspiring, and has been done many times, not just in manga, but also visual novels.
Maybe it'll improve from here...