Ok, this is a really cool concept... have people learn coding by actually coding. I get it, and I am supportive of it. However, the implementation was between mediocre and terrible. Over 60% of the time, when I had a correct answer the interface told me I did not. My codes were identical to the shown answer. If that would happen unfrequently that be one thing. But, it happened as indicated in the majority of the time. And, that was on both a Windows based PC and a Mac OS computer. Within both environments, the interface performed badly.
The above problems caused me to take twice as much time to complete exercises as otherwise. Additionally, it constantly created a doubt in my mind as to my autodidact learning. In other words, it did not make for a good learning experience.
Additionally, I feel like the choice of coding concepts and exercises leave much to be desired. It teaches you a lot of arcane coding that you most probably will have no use for. Instead of 77 exercises, I think the book could have been narrowed to no more than 50. And, within those 50, the focus could have been greater on really practical situations that you could readily leverage in numerous professional situations.