A catastrophe struck the town on May 28, 10:12 A.M. At that moment, the sky and the ground inverted.
3 Volumes (Complete)

An episodic story where everything is connected, sometimes in absurd ways that really challenge your suspension of disbelief. Characters get minimal time to develop before switching to different perspectives, which keeps the pace of the manga rather speedy but the cast a little two-dimensional. A lot of character development amounts to "here's how this person is! SIKE! You were wrong, they're actually THIS!" which, for what it's worth, does make for some unexpected thrills.
Violence was not as gratuitous as I've come to expect with tragedy/survival stories, which really lends a sense of competence to the story beyond shock value. Animal abuse was unpleasant but tied in well enough with the concepts that it didn't feel like animal gore porn, which is fortunate. The manga manages to remain rather tonally consistent throughout its run, with the exception of ONE panel with a goofy cartoony expression that felt ridiculously out of place in such a serious story. The twists play well into the spirit of the manga, so even though they're often sudden, they don't threaten to compromise the manga's voice as a whole.
The art is okay, atypical enough to be interesting but not refined enough to be beautiful. Some 3D models are used for quick backgrounds and objects, which is fine, but noticeable.
However, I must admit, it was unintentionally funny sometimes (the idol twist had me rolling, as did the corpse twist), which I think is the hallmark of either a really good or really shitty drama. Overall, though, it's a pretty gripping story that aptly considers the logistics of a world with inverted gravity, and the sorts of personalities that may come alight in the event of a perceived apocalypse — though, again, these are all exaggerated and interwoven in ways that ultimately remind you that this is a work of fiction.