Tested this for the first time today, using Windows 10 and a nightly build.
it loaded Astrosmash just fine and I had to figure out the controls as nothing came up in the menu - but once I found the in-emu help menu it made sense.
I def agree on the idea of mapping the keypad to the right stick - that sounds brilliant. I usually manually map keypads like so though:
Left Stick U = 1 D = 2 L = 3 R = 4
Right Stick U = 5 D = 6 L = 7 R = 8
LSB = 9 RSB = 0