Incomplete
It doesn't make this apparent in the description that you only get the 3 groups of Kana (vowels, K and S series), and then you have to pay for the rest. Cheap price, and what seems like an ok app, apart from a lack of configurable options, such as turning off the time limit for answering questions, but without clear mention of this not in fact being a free app is misleading, irritating, and will put people off of paying for it. Especially when there are good free alternatives out there. Clarity and honesty wins customers.