Making a Game Boy Game in 2017

Let’s introduce the elephant in the room: the original Game Boy model can only display 4 different colors. Despite being limited to 4 colors only, the Game Boy actually uses 3 different palettes to display images, and that’s very cool! To make a fade-in on a Game Boy, you simply need modify the colors on the 3 palettes.

Source: www.gamasutra.com