...Although my studies in the Japanese language never took off, this certainly helped, and the few friends I shared this with have said the same. So I thought I would share it with everyone!
The way it works is simple. You are shown a syllable in the top left corner, and you must click on the button that has the corresponding hiragana or katakana. Comes with various different modes, for different challenges.
You can now control the game with the arrow keys of your keyboard. Also, not reflected in the screenshots above, there is also a button that will highlight the correct answer for you if you are feeling stuck. ...