Nitpick: it should be "its own little shadow" without an apostrophe.
Lisa told herself she was shivering because of the cold.
I love it. Also the next paragraph. Whatever, there's very little here that I don't like.
One problem I have with it: you switch very quickly between Lisa's and Jack's POVs. Personally, I prefer it when an author sticks to one POV for an entire scene, but I'm sure that can be debated. It particularly stands out when you have lines like:
'Okay,' Lisa said. Jack barely heard her.
It jars a bit, at least to me. On the other hand, this technique really shows the lack of communication between the two, and the bits from Jack's POV are excellently written. Maybe it just needs some smoothing.
The kid's mother used to do this to him all the time.
Another line I love. It shows Jack's resentment briefly and effectively.
Another nitpick: it should be "had run", unless the bad grammar expresses Jack's inner voice.
Speaking of Jack's inner voice, I must say I'm impressed by the rhythm you've given it. It really does seem deranged.
It's "vessel".
I'm really happy you put in the scene where Jack wants to apologise to her. It's a very strong bit, and feels real. (I know from experience that people are never as nasty to one another as when they're ashamed of what they've already done.) The only thing I don't like in this part is "the anger inside him rose into a tidal wave", which is a bit of a cliché. I think you can do without it.
Very slight nitpick: Shelbyville has Speed-E-Mart, not Kwik-E-Mart (unless Lisa crossed over the town boundary to steal).
I find nothing bad about the scene in Lisa's room. It's simply excellent. Particularly good bits was Lisa preferring juvenile prison to her home, and how she would once have enjoyed hearing Jack and her mum having a drink and talking. The bit about the saxophone is great as well.
To sum up: another great addition, with some of the strongest scenes so far in this new version. Apart from a couple of technical mistakes and the switching POVs in the first bit (which isn't bad, just a bit jarring), this is great. I said above that I loved a couple of things in it, but "love" is really the wrong word for something as tragic as this story. I admire it, that's for sure. Lisa is excellent, and you've given Jack an unforgettable character. Not a sympathetic one, of course, but pitiable as well as nasty. You also manage to make it not completely depressing, by bringing in some lighter memories, or Lisa's talking to her Binky. Actually, I think what separates a story like this from the awful kind of darkfic is the fact that Lisa isn't just a victim: she thinks and reasons and tries to make her life a bit better, even when there is no possible way she can.
Specific points about style, since you asked me about that: you needn't have worried, I like your style a lot. (Again, not everyone will, but not everyone will like *anything*.) It does feel quite sparse, but not overly so, and it suits the wintery ambience of the story.
Do keep going.