This looks great! Do agree with others though, that you should expose the course sections. I don’t use vim as my main IDE but I still do use it for quick edits and commit messages, so I don’t know nothing about it. Would be great to see if the course is more/less/same as my current working knowledge. But also a one-time $15 isn’t bad at all, thank you for not trying to make this a subscription :)
Most IDEs have a vim extension that gives you the basic vim editing behavior. It’s great to get into it without having to dive into plugins, buffers, windows etc.