No.1364
Hell has that kind of feeling of being somehow "deeper" than all the other areas in YN, like it's some kind of underlying support structure. Kind of like when you escape out of the testing area in Portal. It has a certain consistency and repetitive nature to it that the other areas don't have.
I think Hell represents the lowest level, or a lower level of Madotsuki's subconscious, one close to a more direct neural rather than psychological level. Of course, a bunch of random stuff still pops up there, since because.