Polystom: Two Universes, One Reality Book

[ in the final fifty or so pages, it is revealed that the whole world might be nothing more than a simulation inside a vastly powerful computer. Or not. I can imagine that if I had read this when I was much younger, and had not previously read, for example, Nick Bostrom's take on the simulation argument, I might have found this mind-blowing. But as it was, I couldn't help thinking it was, for the most part, a bit of a cheap high-concept add-on. I'm not sure it really put much of a new spin on the story told in the preceding three parts of the book. Did it really make much of a difference to what had gone before that, perhaps, none of it was real? Is there some kind of meta-narrative point being made about the fact that what I'd just read was a work of fiction within a work of fiction? Maybe, but I can't help thinking that this late twist felt like little more than a thought experiment tacked on to the end of the story. (hide spoiler)]