I think this game is a better intro to lean than the Lean for Functional Programming book. However I've gotten stumped on some of the puzzles and had to Google some solutions for them since some tactics and semantics weren't explained well enough that I could intuit how to use them. And naturally, I would avoid their use until they are crucial to finishing a level (at which point I needed Gemini would point them out to me). Unfortunately, some levels even Gemini can't help with because it was trained on older versions of the game.