by far the best 日本語 apps i've ever had...
from beginner to intermediate going advanced lessons..
just want to suggest :
should make a personal folder where you pick your own learned kanjis so you can review those group of "learned kanjis" anytime you want... so you won't have to type search them again and see if you're still memorized them..
that's all..everything else is just a bomb. awesome!
kudos and goodluck team..