Which inspires speculation about what it takes to retell a story and if there are any real rules besides the obvious and unhelpful one of if you do it badly, it will turn out bad.
Sometimes it helps if the author keeps his mouth shut. I read, long after, that Andre Norton's Year of the Unicorn was a take on Beauty and The Beast, to which I retort, No, it's not. It takes a motif, albeit a central one, and pulls it out of the story entirely to put in a new one. Great story, the first Norton book I ever read, but I'm glad that it wasn't presented as a retelling.
Not that it always helps. Watching one Thief of Bagdad remake, I nearly groaned when I realized that two characters were out to play The Fisherman and the Genie in front of me. Then, a little while later, I was watching the original, accept-no-substitutes, silent Thief of Bagdad, and the princess's three wooers had collected a magical apple that healed, a spy glass that would see over distance, and a flying carpet. And they were about to go on, and I was on the edge of my seat until one of them said, Let's check out what's happening in Bagdad, much to my relief, and they went on to re-enact the story about how you can't chose one of the magic things as better because without every one of them, she would have died. And I haven't any notion why one was great and the other stupid -- though surroundings helped, the first movie is unquestionably the better.
Details help. A lot. I didn't like either There And Back Again, Pat Murphy's SF retelling of The Hobbit, or Jenna Starborn, Sharon Shinn's SF Jane Eyre retelling and in both cases, I thought they had filed off the fantasy/mundane serial numbers and never quite inscribed their own. Robin McKinley's Beauty managed to fill in lots of details, though at that, it had its own change -- Beauty's sisters are perfectly loving and not the vicious ones of the tale. Patricia McKillip managed it in "The Lark and the Lion" too, though that one was as much style and detail.