Doomsday super system

The end of the world is coming, terror has enveloped the whole world, and the earth has become a hunting ground for zombies and mutant creatures. Zhao Tianlei (male protagonist) accidentally acquired a mysterious super system. Although he is not a saint, but seeing the tragic situation in front of him and the deaths of his classmates, how can he stand by and watch Zhao Tianlei, who has a super upgrade and exchange system, How to lead humans to fight against corpses and restore human civilization.