Just an observation. The change in difficulty over the entire Japanese course feels uneven. Somewhere in the later third to quarter, it feels like the exercises and sentence structures get a lot more difficult without adequate preparation. It's possible this would be helped if there were more and better grammar notes for all the exercises. It would also be nice if grammar notes were available directly in the mobile app (yes, you can go to the website in a mobile browser but that is a bunch of extra steps when they should be supported in the application itself).