Witch's Girl a browser CYOA framed as a children's story, and combines gently snarky humour, simple but charming illustration and a turn-to-page-N conceit to suggest a picture-book. Two small girls, Oblivia and her best friend Esme, encounter a witch who directs them on a time-travel adventure to save their (slightly hazily-defined) fantasy world.
The emphasis here is rather more on the adventure part than the saving-the-world part; in a few important respects the story resembles a game of make-believe more than a work of authored fiction. The long-arc plot is conspicuously an excuse to run around and have adventures, and is often temporarily forgotten in favour of more immediate distractions. There's a pleasantly childlike focus on the cool stuff that's happening now; but there's also a certain snarkiness about the whole enterprise that gives it a more disaffected grown-up feel at times.
Structurally, a degree of puzzle difficulty is added by a time-travel mechanic; in order to find items to solve gateway puzzles and advance to the next stage of the central plot, you need to use the witch's cauldron to travel back to earlier points of the plot and choose alternate paths. This means that you have to consume most of the game's content in order to win. Towards the end this devolves into lawnmowering through all the options, but it's less annoying than it could be; finding the last few items took about the right amount of time, as far as I was concerned.
My feeling was that it could have benefited from a little more use of state; it's a game about collecting items that doesn't have an inventory, which can make it a little hard to keep track of things. And it'd have been nice if there had been slightly more illustrations, more evenly distributed through the text. But overall, a pleasant experience.