I can't judge it as an educational tool since I already know hiragana (therefore no point to the exercises in my case) but the story itself was rather hilarious and unexpected - even after reading the draft on paper beforehand.
The sprites are cute and the whole thing managed to have some consistency at the end but not quite enough to "feel" polished, which is something more people should aim for when time constrained.
I'm hopeful that the final product will be as ABAP as possible. This is a good start.