I stumbled upon this awesome app but it need some tweaks.
For example, the landscape mode seems to have some problems especially after getting out of editing mode or when launching the app. It often go back to portrait mode and then turn back to landscape, which is a bit annoying. Also, when studying, the answer buttons are not repositioned in landscape mode so the text is written vertically. Maybe use icon instead ?
Another killer feature is to be able to create your own study board but the problem is you probably want to use the existing material, which doesnt seem possible right now. As an example, I use the excellent Japanese app on iPhone and you can create your own list of any damn thing (particles, verbs, adjectives, name it) and make your own study set out of this.
It would be awesome if you could create a custom board out of existing material because when encountering new words in life, it doesnt really fit the "academic" order and you might want to study that right away, which is downright impossible right now.
JPLT Grades are also pretty daunting if you just begun learning Japanese. It would be really good if you could start with school grades instead, like the iKanji Touch app.
The very best thing would be to have a writing practice feature to learn how to correctly draw the kanjis since its the real way the kanjis will stay in your head.
Fix those and you will have a killer app! :)
Good job!