i just read the first book and i loved it. totally recommended for beginners who want to enjoy reading a piece of manga (or text in general) in a non painful way.
in my case i did not have any expectations at all (i have wanikani, genki 1 and a private teacher to learn proper japanese) and i wouldn’t encourage anyone to expect to learn proper japanese just by reading these books/guides 'cos, imho, crystal hunters aims to give a grasp of the japanese language you find in manga in a very simplistic way. still the guides (maybe not 100% accurate with everything they say) are quite complete.
also love the idea of having two versions of each book: one with a super simple language (including furigana) and the other in (still simple) natural japanese language
already bought the rest of the books