Thanks for all the nice comments!
I made this specifically for folks who've only used GUIs and are used to having a designed shell around everything they do. That's why I illustrated the windows — at the small expense of readability, the goofiness/friendliness makes the topic more fun and less intimidating.
As shazow mentioned, I'm working on specific Linux (very few changes) and Windows versions (including instructions on using the Linux subsystem), and hopefully doing others on topics like git and whatnot — same model as this one, no signup forms or payments. That said, I am looking for sponsors to help fund my time in making these. If you (or your company) is interested, send me an email at tracy@hellowebbooks.com :)