When I discovered this product, I was a bit confused about its nature. Indeed, I didn't know if it was a game or a book, as I was only reading without the possibility to interact. This led me to think that it would be more appropriate to add choices or interactive elements to make the experience more like a game. Indeed, I think that this would allow to engage the users more and bring an additional playful aspect.
In addition, it might be interesting to offer a downloadable version of this product, so that users can easily access it from any device. This feature would be especially appreciated by users who want to be able to access it offline or in areas with a limited internet connection.
All in all, I think these two elements could add a lot to this product and improve the user experience considerably.