Welcome to the world's first Advent calendar for Gameboy:

Christmas is in danger. Travel back to the Advent season of 1989 and help Santa get rid of the chaos from back then. In 24 days you have to find gifts, clean up microplastics, fight Krampus and bring back peace to the North Pole. Only if you succeed, Christmas can be saved for all times.

Check it out here: https://steti.itch.io/x-mas-time