This is an interactive vim trainer: a target lights up in a code buffer, you move the cursor onto it, and the game immediately shows the shortest key sequence you could have used. Instead of reading about motions, you learn them the way you learned to touch-type — by repetition with instant feedback.
vimtutor and cheat sheets teach you what the keys do. The hard part is when to reach for them — recognizing in half a second that 3fa beats holding l. That's what the live “shortest” hint teaches: after every target it shows the optimal motion, so each round quietly corrects the habits a tutorial can't see.
A few 60-second rounds a day beat an hour once a week. Pick one motion family per session, deliberately use it even when it feels slower, and watch your keys-per-target average fall. Because the trainer runs full vim emulation — including your own vimrc mappings — everything you learn here transfers straight to your editor.
Once the motions feel automatic, benchmark yourself with the vim speed test. Neovim user? The nvim trainer covers lua keymaps and relative-number jumps, or read what vimtyper is.