Retroarch Launch Menu, Change Default Emulator, Fix NES Paperboy Controller Not Responding Issue
By default, RetroPie for Pi0 and Pi1 uses quicknes for NES emulation. quicknes is known for its performance and efficiency, however, it does have a bug with Paperboy, which receives no inputs from the controller, rendering the game unplayable.
The fix is quick and easy: changing the default emulator for rom to either nestopia or fceumm.