The term “fanservice” probably doesn’t apply well to a manga like this, despite the high amount of nudity. It appears to be a fairly typical seinen type of manga, one that is weird and full of shocking imagery, similar to Heaven’s Prison. Nudity is often part and parcel of shock value in this genre, even if fanservice isn’t on the menu.
As the manga progresses, there eventually reaches a point where Kurozuka loses interest in the “artistic” topless shots and starts moving on to sex acts and far more explicit depictions. It is rare to see lower body nudity uncensored to this extent in a standard manga and the depictions of sex acts go pretty far as well.
The art is spartan at best and almost grotesque at it’s worst, but I think such an art style is fitting given the all around extreme nature of this manga.