They do fun browser-based diversions – text-based choice games, which have fun stat-changing decisions and chapters. You can be a roaring Dragon or take part in a Hornblower-esk Navy adventure.
I never really seriously read “Choose your own adventure” books – I did have some but always cheated just to check out how the books worked, which was much more fun. Drawing out maps, getting through the game, was the fun part.
These however are fun and entertaining in their own right – and quite intelligently done. You get several chapters, several vignettes (they explain how to write your own, the blog is great at explaining the choices behind their games (including on genders). Also; nice theme 😉 ), which all press you into deciding some major action or other. It’s done so well and gives you a lot of agency – as they explain in their “Why” section.
I’ve not replayed any however; mainly because I’ve been fully satisfied with my own mini-adventure, being a Dragon or a member of the Royal Navy! I expect the choices you do make can be, as in most games, variable between a small change in text and a entirely different branch (and perhaps early end to the story). The interestingly devised stats change outcomes, and it does a great job at making it book-like without taking away your own agency – the actions are widely different a lot of the time.
In any case; these are easier then text-based adventures to navigate, fun to leap into and enjoy, and also are well written. Give them a shot if you’ve got half an hour or so to spare 🙂