Explaining the appeal of Inuyashiki, taken from my instagram:

Inuyashiki is a manga from the mangaka behind Gantz and is important as it shows that Oku (the mangaka) has the capability to create not one, but two fantastic works of fiction. He took some of the best and often underused elements from Gantz and put a lot more focus on them. This gives Inuyashiki its own identity despite coming after the massive success that was Gantz.

Unlike Gantz, Inuyashiki is a story that focuses more or less exclusively on the two main characters and those who they interact with. There are still the occasional side stories that Oku has grown so accustomed to implementing into his core narrative, but for the most part Inuyashiki feels more personal. Perhaps the best thing about Inuyashiki is the two main characters, more specifically their extremely contrasting personalities. On one hand, there is a caring old man who desperately wants to be be loved by his family who have grown cold towards him. And on the other hand is a student who, despite being popular at school, cares for no one but his childhood friend and would do anything to protect him. Upon receiving power, both of these characters have polar opposite reactions. The old man uses his for good, attempting to help anyone in need, whereas the student uses his to murder entire families in their homes. These two characters are the personifications of good and evil. It is this character dynamic that drives the plot forwards and keeps you engaged. The two very different ideologies that these characters posses lead to some great conflict.
As for the art, as you may have expected from Oku, it is absolutely brilliant. The art in Inuyashiki is even able to surpass Gantz in some aspects, this is mainly due to the more advanced technology that Oku now has at his disposal. Similarly to Gantz, the art is very realistic and helps to ground the story in reality.

Inuyashiki was clearly made to be more of a character study, which I think worked well, considering Oku seems to have already exhausted every possible idea when it comes to a large scale narrative in Gantz. There is a decent anime adaptation of Inuyashiki but I would still suggest you read the manga over watching the anime
Score: 9/10