This is my favourite app for learning Japanese, and I have been downloading and trying so many by now that I feel like my perspective is valid.
At the time that I found this app, I already knew hiragana and katakana, so I was mostly drawn to the grammar portion of this app. I especially am loving the way it uses kanji only when introducing words (in my case, I know how to say these vocabulary words but may or may not have learned the kanji or how to conjugate the verbs/use them in a sentence) and it is really helping me understand. I like the way the wordbank grows throughout the "levels" so that you actually have to know which kanji are what, even though the lines they fit onto may give you a little hint, Im finding this still very useful.
This app will help you familiarize yourself with kanji, and help you understand the grammar/sentence structure of the language. Im liking it so much I just had to leave a review. Hope this helped!
NellieFaith about Learn Japanese!! - Hiragana, v1.1.10