There's not much that I can say about the series that would not be a spoiler. But you have to work hard to understand what is happening: the narrative is dense, fast-paced and complex. While it may look like a dumb action-oriented series, based on the carnage shown in the OVA, there is actually a method to the madness.
And it is madness: the backgrounds are complex CGI-rendered vistas, with CGI-generated 'things' swimming through the air. There is movement everywhere, so it is easy to become distracted. Plot-points are not narrated by two static characters talking: the series is quite dynamic -- and if you get distracted by the animation, you might miss it.
So yes, this series makes you work. But if you put in the effort (or maybe even rewind for a bit if you've missed something), you will be rewarded by a story that is both epic (as in: literally world-shattering in scope) and personal (as in: dealing with the inter-personal relationship of the characters). That's hard to do, and even harder to do well -- Kyousogiga succeeds. The series is only 10 episodes (and one of those is effectively only a video-clip for an image song (though that song does explain more about the plot)), and yet by the end you care about these characters and what will happen to them.
It looks gorgeous, it's wacky, it is packed with a dense plot, and it is also character driven. I liked it a lot more than I thought I would, judging from the OVA and the first episode. I'll give it an 8.