Pizza Boy is an unlicensed NES game about a noseless boy who delivers pizza. The controls are pretty bad.
As with many Nice Code games, pressing Up, Down, Up, Left, Right, Left, B on the title screen will briefly display a credits screen. Unlike most other Nice Code games, it doesn't list any of the developers who worked on the game, instead only displaying the "PJ" ASCII art. PJ most likely refers to the Power Joy series of Famiclones which many Nice Code games have been released on.
Hen & Sons
An alternate version of this game (misspelled as "Nen & Sons" on the title screen) exists which replaces the graphics. The code to access the hidden credits screen was disabled in this version.