Kirby Tilt 'n' Tumble, known in Japan as Korokoro Kirby, is an action puzzle video game published and developed by Nintendo for the Game Boy Color handheld video game console. It was first released in Japan on August 23, 2000 and in North America on April 11, 2001. Due to the cartridge having a built-in accelerometer, it has a unique shape, as well as a unique transparent pink color.