I have read several King in Yellow stories that hint at various bits of the text, each with their own approach to the imagined play, and this one's approach seems to be designed to get around the problem of how a straightforwardly written narrative would be unlikely to drive someone insane, by implying that it's something deeper beyond the words, and/or one's endless interpretations of them, that makes the play mesmerizing. While not a huge variation on the concept, it's an interesting way to deal with the problem of imagining a viral text.
But beyond that, it felt a bit creepy pasta to me, and not in a good way - character meets creepy object, is driven to madness by the codex, grimoire, whatever, and then does bad things. The telling of the story, while above average in execution, doesn't quite elevate it beyond this familiar level for this kind of story that is easy to find these days. I still like this kind of idea, but something more to generate interest would have been nice. For example, Ramsey Campbell's old story of mixing forbidden Mythos texts with more familiar and sometimes censored forbidden texts from popular fiction in Cold Print was a fun variation on the concept.