I'm not exactly sure what anime this comes from, but the doujin has some satisfying art. The story, well it's rather short and simplistic, but the artwork and action compensates for that. Overall a successful doujin.

In conclusion, this doujin, Exocist, receives a 4 out of 5.

A very ameturish art style makes this appealing to zip through. Pleasing images on each page, and it's in full color to boot.

The jumpsuit the main character is in makes her look very shapely, as if no clothes were worn at all, but gives the excitement as it doubles both as a teasing suit and a catsuit, an otaku's cliche.

Her expressions could have been a bit more extreem, especially when she takes it in the rear, but still good none the less.

I'm not familiar with the source material, so I'll just focus on the content.
Well color is always a plus so points there. The art is is crisp and sharp, very clean lines and a good overall finish. Not a lot of action taking place and hence not a lot of pages make it up, so a minus there if you are looking for quantity. The story is entertaining and if you're a fan of cat girls (ok, a girl in a cat costume, if you must split hairs) then big win for you. If it had just a little bit more to it, I would have given it much better marks.