At a glance this seems to be an interesting program, and they even did a talk about how they are successfully monetizing at VimConf 2021 https://www.youtube.com/watch?v=soxBUGYOaLA
If nothing has changed, I dislike that it is not upfront about the paywall that comes after you've spent some time on the very basics; it would be honest to disclose that before people start.
I'm sure there's better Vim learning tools these days. Though it should be noted that learning to use hjkl doesn't remotely begin to cover the expressiveness of vim keybinds for editing, and I think this tool at least goes more in depth than most others.
edit There was not a paywall when I did it. Bummer.
It helped improve my vim muscle memory substantially. Well done imo.
