Ask panjak/herr-jak/Umbrella Warriors dev about the noise. He managed to mostly fix it when I was helping him debug Mega Q*bert on real hardware.
The slow motion function just causes it to press pause every frame until you tell it to stop, and since pause resets to the title screen, I'm guessing it's an issue in sprite loading.
Forgot to mention, there's no 6-button support obviously, but holding MODE during boot doesn't remap the x y or z to the other buttons, like what it's suppose to do for games that specifically don't support it.
If you need any more help with real hardware feel free to contact me outside of the demo days.