Wordoko for Android
Polished, simple and effective. Devs: some humble suggestions, 1) an option to increase the font size, as the characters can be hard to read and 2) furigana above/below kanji so that we learn what kana goes with what kanji. Nice work. (^^)
by Q####:
This game is not free! After the install it has a sample and then they want to charge you for each time for seperate sets of crosswords.