Not worth it
I spent $40 on VIM Adventures, and it wasn't worth it. The early levels are great for learning basic VIM commands, but the later ones turn into overcomplicated puzzles. Instead of building VIM muscle memory, you end up stuck figuring out how to solve the puzzles themselves. Progress becomes very slow and frustrating. On top of that, access only lasts six months and the site has annoying quirks (for example you often have to re-login and reload your saved game if you've been away for a while). So, overall, good idea, but poor execution for actual VIM training.
By D.T.