Ok wait guys I just hatched an idea about .flow
Sabitsuki is a krokodil user. Krokodil is, essentially, the heroin version of what crack is to cocaine. You make it at home in about 30 minutes with over the counter ingredients, but because of the ingredients you use it causes a slew of ungainly side effects. This would explain the mysterious flesh eating "disease" she has - krokodil is mostly known for its horrific flesh eating abilities, ranging from losing fingertips to having your entire bone exposed with mucus-y flesh hanging off of it. Which could also explain the Tumbling Doll effect, the Machine effect, the Viscera effect, and the general rotting atmosphere of the game. Not to mention the ending with the chainsaw maid - that could possibly be Sabitsuki attacking a paramedic in a drug induced frenzy and having to be a quadruple amputee because of the damage??
Not only that, but she appears to live in a dumpy apartment in the middle of a dreary, cold place. Russia, the place where krokodil is easiest to manufacture and most prevelant, is pretty damn cold and dreary. And as I said before, krokodil is a pretty cheap ass drug, so we can assume the reason she's not using actual heroin is because she can't afford it.
This is a pretty discombobulated theory and doesn't explain a lot of her dreams, sorry, but I was really excited about it.
For more info on krokodil, check it out here: http://io9.com/5859291/krokodil-russias-designer-drug-that-will-eat-your-flesh
(WARNING! The link contains photos that are not for the faint of heart.)