So many language apps are just flashcard sets. But knowing hundreds of words doesnt do you any good if you dont know how to put them together into intelligible sentences. Human Japanese actually shows how the language works. Yes, that means it spends lots of time on grammar, but it manages to do so in a way thats actually really interesting, more like decoding a mystery than just giving a bunch of rules to memorize. The quizzes are on the simple side, but still great learning tools. The real genius of the app is in the explanations and HUGE number of example sentences. I highly recommend it!
BobRobinowitz about Human Japanese Intermediate