This story really is so good.I loved the shift as the narrator first identifies the woman behind the wallpaper, begins to observe her, and then eventually begins to think that she is the woman from behind the paper, who has escaped into the room. Our POV character is suffering from postpartum depression and can't spend time with her child without feeling nervous. The second is that she is a woman with an active imagination, a rich inner world, who perceives things around her very closely and prescribes meaning to them. This is framed as a feminine trait and is contrasted to the more rational or level-headed perspective of her husband (who gets a name, when she doesn't). The combination of these things, made more acute by her being trapped in this room where she is not allowed to go or do as she pleases, is making her lose touch with what is real.
There is a romanticization of these old, possibly haunted houses by Perkins Gilman's characters. This is true of our POV character in this story, and also of the characters in The Giant Wistaria, who take up lodging in an old house with the hope that it might be haunted, because that would be romantic and exciting. But this desire for ghosts and excitement quickly breaks down when the characters are faced with the reality of those experiences. They become less romantic and more just ... frightening.
The room is in such disrepair that it makes you wonder what is true. Is this all the result of our narrator chewing and denting and ripping, or was there someone trapped in this room before? The story suggests it was a child, which has some really eerie implications.
I liked the way the wallpaper represents the narrator's experience of confinement, and that she can't escape the confinement that her husband has placed on her, so she has a mental break that allows her to imagine she has escaped from behind the wallpaper. This story reads very ahead of its time, and I can only imagine the shocking impact it had on its contemporary readers.