In general:

* It could be a little more obvious how to navigate to the now playing screen. My suggestion is to have a now playing bar at the bottom of the screen like most other music apps.

* How do I view the currently playing playlist? When I tap on "shuffle all tracks", it generates a new playlist of all my tracks (in a shuffled order). When I navigate away from that screen, I don't know how to get back to it. When I tap on "shuffle all tracks" again, it doesn't take me back to the currently playing playlist, it generates a new playlist.

Android specific:

* The lock screen widget could use some tweaking. I have adult male sized fingers and I feel like I'm playing that old Operation game when I tap the pause/play button.

* Why no widget for the home screen?