Wow, this is really good. The SoL-ish side of this really helps on the Character development and getting attatched to them, find myself actually caring for what is going on here, thats rare.
Having most of it from the view of Yuki makes it quite brilliant, the flickering between what she sees and reality. Usually when they are on a safe area (or moment) we see everything clean and lively, but when they have to deal with what is actually out there it shows the level of decay that the world they live in actually is in. Keeps the brooding atmosphere mostly as an undercurrent instead of all over your face, the flickering between them is enough to remind you of that.
I am impressed, and this is getting an anime? NICE!