From the Tindie blog:
When they first came out, the Game Boy models were the cream of the crop. Even the original DMG model, the screen looked stunning for the time. Despite nostalgia being a powerful thing, the screens haven’t aged well in our post-4K world.
A great way to breathe some life into that screen is to use a bivert module. These modules enhance the contrast of LCD displays by biverting/inverting the pixel orientation on the screen. The difference is pretty noticeable too, with a sharp blue appearance and better grayscale saturation.