Reborn as a Mouse in the Apocalypse, I Somehow Have a System

[Apocalypse + reborn + zombies + System] The protagonist unexpectedly dies from overwork after an extra shift and transmigrates to an apocalyptic world overrun by zombies, where he becomes a rat. To his surprise, he comes with a mysterious System. Thus begins his arduous struggle to survive in another world in the body of a rat, and his journey to turn the tables and become the king of the apocalypse.