Super Mario Land 2: 6 Golden Coins

"Super Mario Land 2: 6 Golden Coins is a platforming game for the Game Boy and the sequel to Super Mario Land. It also marks the debut of Mario's self-proclaimed arch rival Wario, who would later become a recurring character in the Mario series as well as a protagonist in his own series. The game features new graphics, power-ups, challenges, and a completely original storyline."