Change Background Color
This code requires a Super GameBoy.
Enter one of the following codes during game play to change the background to match the corresponding GameBoy case colors.

Code Color
Hold Start Green
Hold Right + Start Red
Hold Up + Start Black
Hold Down + Start White
Hold Left + Start Yellow

To change to the transparent Game Boy, sweep the D-pad continually in a Full-Circle until a tone is heard. Hold the D-pad in that direction and press Start