The Premium version contains everything of the the free plus Random and Repeat. And some extra features like a function to show what's playing.
You need to produce energy to charge this player - shake it or move with that. Perfect jogging companion - it plays while you run.
* It doesn't charge phone battery, but mimics that.
GUI, small fix
See also Human Powered Torch app
More from developer
The free edition contains Play/Pause, Next and Previous Track.
Get Premium if you want more features, like "Random and Repeat".