Who is the other girl? Is it Yukari?

Given that she appears to be sleeping,I'd say yes

紫様=Yukari sama

And...err.....what about dead space ?

Dead space refers to an area in a picture where nothing is going on, with the connotation that it detracts from the picture as a whole. Basically the artist is acknowledging to his viewers that he screwed up the composition, but decided to post it anyways.
Ironically, the "dead space" written in the circle fills up the dead space in the picture. If you shopped that part out, (or tried to picture it in your head), you might get a sense of how the work feels unbalanced, like it's begging to have something on the top left. I keep thinking it'd be good marginalia in some book, although what the book would be on I don't know.

TubercularOx said:
Dead space refers to an area in a picture where nothing is going on, with the connotation that it detracts from the picture as a whole. Basically the artist is acknowledging to his viewers that he screwed up the composition, but decided to post it anyways.
Ironically, the "dead space" written in the circle fills up the dead space in the picture. If you shopped that part out, (or tried to picture it in your head), you might get a sense of how the work feels unbalanced, like it's begging to have something on the top left. I keep thinking it'd be good marginalia in some book, although what the book would be on I don't know.

I prefer to think that Yukari or Ran just really like Dead Space and plan to by it when Rinnosuke gets it in stock.

TubercularOx said:
Dead space refers to an area in a picture where nothing is going on, with the connotation that it detracts from the picture as a whole. Basically the artist is acknowledging to his viewers that he screwed up the composition, but decided to post it anyways.
Ironically, the "dead space" written in the circle fills up the dead space in the picture. If you shopped that part out, (or tried to picture it in your head), you might get a sense of how the work feels unbalanced, like it's begging to have something on the top left. I keep thinking it'd be good marginalia in some book, although what the book would be on I don't know.

In fact, when i was in Art class in college, they said that it could be a good thing to leave a dead space in a composition, has it can add dynamism.

Now I want to think of the game in the sense of the art concept.

I feel like I need a new level of snark for such a task.