All the thirteen stories have something to do with health, sickness and something like that. Either the protagonist is sick, or someone he knows, or someone he hates. I think if the title of the book is not to be taken literally, sunset could mean being at the last few decades (because days will be too short) of their lives.
I have read a few short story compilations of Stephen King but it was too long ago for me to recall those books. But if I remember it right, this is different from all of those other books I have read. I couldn't remember in which compilation does "Rita Hayworth and the Shawshank Redemption" belongs (I'd be glad if you can tell me at the comments the book where it belongs), but that is the most memorable short story for me amongst all of them, "Stand By Me" being the second.
In this book, the story that got stuck in my head up until now is "Stationary Bike." Please refer to my post about the story. It is striking in as much as I wanted my best friend to read about the story even if I know that she doesn't read Stephen King books. Not to mention the fact that this is the first time I urged her into reading something.
It took me a while to finish this book. One of the major reasons is the number of distractions around. But the other reason is that I find it not too engaging as compared to his other books, to make me sit and really read and not bring down the book.
But after all, Stephen King's style still amazes me. Sometimes, it is not necessarily the story but those little things inside the story that makes me wonder how can someone think about that piece of a thought.