Game Boy System Cheats (GameBoy)

Other color schemes (as stated in the manual) may be selected at the Game Boy logo by
pressing the following combinations:
 

Up: Bright Red

Up + A: Red

Up + B: Dark Red

Down: Pastel

Down + A: Orange

Down + B: Gold

Left: Bright Blue

Left + A: Dark Blue

Left + B: Grey

Right: Bright Green

Right + A: Dark Green

Right + B: Invert Colors 

While playing a game, press A + B + Start + Select to reset most Game Boy games.

At the Game Boy logo, press Right + B to reverse the screen and sprite colors. This may
make the game easier to see in dim light.

While playing a game, press A + B + Start + Select to reset most Game Boy and Game Boy
Color games.