The Game Boy was
Nintendo’s second portable gaming system, and the game where Kirby made his debut.
This stage features a grey Game Boy with a green monochrome screen that scrolls through the world of Kirby’s Dream Land. It begins first with the Game Boy's opening screen, then starts going through two parts of Green Greens, and then in King Dedede's castle before transitioning to outside of it, and ends in Dedede's boss room prior to looping once more.
Hold Y while selecting this stage to change the color of it to black and white.
Text by MGZXYOLO & Smashedpotatoes