App resets spoil overall goodness
I rely on this app for learning Japanese vocabulary, and it is basically very useful for that. However, if I’m in the middle of a long learning/revision session and interrupt this for more than a few minutes (e.g. to prepare and eat dinner) the app resets and I have to start the session again from zero. Please either get rid of these app resets or - at least - make them optional. They spoil what is otherwise a good app.