No.1413
I love Plastic Girl. I feel like the theme of "escape" and symbolism is something both YN and Plastic Girl share, though I think Plastic Girl is a lot more in your face than YN. It's quite basically a story about puberty and growing pains.
The protagonist of Plastic Girl feels bitter about and alienated by her parents, who she believes prefer her as a baby they can suppress and control (especially her mother, "Mommy spawned me so I would bear all her sins", "Mom gave me a name. Secretly, I give her one back" - harsh) so she acts out by "turning ugly" when not given attention and "forgetting" what it means to be human (emotional issues), "having a baby" she kills to avoid getting in trouble, drawing "angels" to her and then gutting them for fun (relationships), etc.
She feels completely detached from her much younger, more naive self and feels like a totally different person from the baby her parents loved so much. She wants to escape from those feelings, so she tries going "Well fuck you. I'm going to become an adult as soon as possible and you can't stop me". She bites into an unripe, "forbidden" fruit, but it only hurts her in the end.
I also think her alienation might get to the point where she feels like she hurts and discards other people (she kills the snake she was "playing with" and stones the girl who directed her to her home to death) and is actually sort of disgusted with her "friends" (like the one who was "making a human being").