FanficRecs Beltane Night
Beautifully written. The descriptions come across vividly, and the characterization feels spot-on. There are hints of the twist, if you know where to look (and, for me at least, if you recall one particular line from the original film), but it is by no means merely given away. This is definitely one to check out.
FanficRecs Comment by Anonymous
Seconded. All of her Labyrinth fic is superbly written with believable characterization and lots of mythology nods.
FanficRecs Comment by Yessiika
One of the best fanfics this troper has ever stumbled upon. It features a strong-willed, believable Sarah (one who isn't totally derailed into the author's Mary Sue or else completely flanderized) and a truly antagonistic Jareth. A little short (with only three well-lengthed chapters) but superbly written, with some beautiful Greek and Celtic mythology nods, and featuring a plot-twist you'll never expect.
FanficRecs Not fluffy at all
The author says in the beginning notes that "if you're looking for Fluffy Jareth, you won't find him here." The author delivers fantastically on this, and it's the perfect story for people who enjoy a darker Jareth.
Sarah is also strong-willed, though she definitely falters a few times. The author balances it out just enough so that you're not sure whether she will actually win or not.
As other reviews mentioned, there's a very nice twist at the end that you won't see coming, but you'll definitely find hints pointing at it upon rereading the story.
This is one of my favorite fanfics. That's "favorite fanfics," not "favorite Labyrinth fanfics." Among the hundreds (thousands?) of fanfics I've read in all my fandoms over the last fifteen years, this one is definitely in the top three.