In my humble opinion Mr. Penaz, you've already done a swell job.
I can personally recommend you take a much needed break.
Burnout is not something to be ignored.
There is an issue that has been pestering me.
Despite my personal recommendations of your book, most of the gamedevs who use these engines respond apathetically:
"C++ is too advanced, Python is unoptimized and is not meant for games and finally pseudo-code has a notorious reputation as not being a real language."
That's the general opinion of most of the 2D gamedevs who I have encountered nowadays who make use of just two game engines: Gamemaker and RPG Maker.
Though I'm not recommending you write a version using GML,
I do insist that you ought to consider writing another version of your
awesome book in the standard languages of Ruby and JavaScript.
Sure JavaScript is not that OOP oriented as Ruby is, (I'd prefer Ruby) but these couple of languages would make a much bigger impact than the current versions.
Just don't inflict self harm on yourself Mr. Penaz.
Cheers!
P.S. Not many use Ren'Py or Godot where I'm from.
* Opinion from India *