Wow... just stumbled in here today and glad I did. These are amazing thankyou.
If you ever decided to make this or your Retrofab emulator work correctly on phones and tablets, it would be very cool if you could somehow tap into the gyro so that the orientation of the handheld could change depending on the angle of the device, ie; tilt the device to the right and see more of the left side of the handheld, tilt to the left and see more of the right side, up/down etc. There are a few phone and tablet apps over the years that have done this with pinball games and also Labyrinth games. Check out this labyrinth game from 13 years ago to see what I mean.