Nice COSINE Doujin, featuring some black & white images from the full color CG. As far as I know, first was this, then the CG, so, this was a sort of "EP". Great artwork, the COSINE style is easily recognizable, and it's simply great, even if some peole are moaning about the futanari content.
Final Call: Worth to download, or just simply go to the full color CG, it's your choice.