Love this instrument. While it certainly cant compete with the real thing, the sound is quite good. The tones are beautiful, that even random tapping is pleasureable to listen to. You cant play a sour note.
As far as improvements are concerned, I agree that the layout needs to be improved. The edge tones are too close to the main tones, especially the one at the center. As it is, I think the layout sacrifices playability, perhaps partly to maintain a visual likeness of a hang drum. It seems playability should come first. I also agree that the output could be a little louder, though it sounds great through the earphones.
Bottom line: well worth .99 for hours of soothing creativity.
yukkuri_kame about H4NG