The short review is that this is a story about a porn actress who has the ability drastically increase her physical size to gigantic levels combined with Tokyo getting hit by a number of disasters of the natural or unnatural variety. You will like it if you enjoy an author's attempt to visualize the largest breasts of all time, but also don't mind reading a story with more holes than the female lead.

In greater detail:
Since this story is by Oku Hiroya, you're know what you're in for. Violence, guts, death, gore, nudity, sci-fi and action. That's all fine and dandy, after all if you're scared of a few beheadings in media in this day and age, you probably haven't looked at the world very closely. The problem here is the methods in which the story is advanced or told. McGuffin-level coincidences are forced to accelerate things along to the reason everyone picked this up in the first place, and there are large sections of story where very few words are spoken at all. I know we're supposed to be shown, not told, but some talking would be useful sometimes.

The art is the best aspect of this manga and is fairly well done. Oku has had a lot of practice at this sort of thing and there's the usual imaginative evils for the good guys to clash with. If you've made it this far, you probably already know there's at least two big reasons you're reading this manga.

There are two main characters, the male and female leads.

Our male lead, Rei, has no special abilities short of being a nice guy in the right place at the right time. He has done and appears capable of nothing noteworthy. So far, he could be replaced by an emotionally supportive dildo and it very nearly wouldn't change the story.

The female lead, the one you're all here fore, is Papico the porn star. She is designed to be every male's dream woman: Incredibly beautiful, desirable, emotionally needy, wanting to please her man, but yet also ready to be a super buttkicking badass at a moment's notice. What can't she be?!

That's it. The male acts so you want to be him, and the female acts so you want to get with her.

It wasn't as unenjoyable as it could have been, to be honest. You can really blaze through it because there's so many pages without any words on them, unless you want to take an extremely close look at body parts, both attached and unattached.

Overall, you know what you're going to get. There is no secret awesome sci-fi story here that's being overshadowed by giant round flesh orbs, so no need to pretend otherwise.