[nomilk]

I paid for it, was worth it for me. Reason: I did vimtutor 4 times and was learning but found it super painful/boring, but really wanted to learn vim keybindings. Vim adventures made learning keybindings and muscle memory just tolerable that I could do 1h in the evening even after a long/busy/tedious day. I probably would have persisted learning vim keybindings without it, but it definitely made doing so less painful.

[merelysounds]

A free alternative for learning just hjkl, nethack supports this way of moving[1]. Remember to keep your index finger on ‘j’ (don’t shift your hand to ‘h’), to build the muscle memory.

[1]: https://nethackwiki.com/wiki/Direction