not problem for one hand. in fact, you don't need to press the other bottoms because it is very easy to control the volume and choose one sound tracks by the wheel and the play key. for example
turn the wheel when playing, you will go into a new screen like below so you can choose the other sound track.
if you press the play bottom more than 2 second, the volume control pop up so you can adjust the volume.
it is quite simple for use. of course, you can press the play key for play or pause
It looks easy, but what about the bugs?