I probably should make an XHDPI version of the virtual gamepad, since the small controls has been brought up before. The difficulty is the "corner cases", where the app has to make a decision based on the screen resolution and dimensions, whether to use the tiny, small, medium, or large button images, and whether to use a tablet layout or a phone layout. It still gets this wrong on some devices, and adding another choice to the mix increases the likelyhood of wrong choices being made.
That said, I can throw together a couple custom layouts that you can add manually.