My Apocalypse System Awakened Five Years Early

After burning all of his savings on a gacha game, Klaus Murrow awakens the Apocalypse System. However, there is one big problem: the apocalypse hasn't happened yet. The system is five years too early and mistakes modern society for a post-apocalyptic wasteland, and begins rewarding Klaus for surviving. [Host has found drinkable water!] [Host has found edible food!] [Host has found a safe shelter!] [Host has leveled up!] He accidentally steps on an ant. [Host has killed a mutated monster!] [Host has leveled up!] He saves a kid from a dog. [Host has saved a human from a mutated monster!] [Host has leveled up!] While the system desperately tries to prepare humanity's future savior for the end of the world, Klaus quickly realizes he can exploit its mistakes to grow stronger at an absurd rate. With five years before the real apocalypse arrives, Klaus plans to use every loophole he can find to become strong enough to face the coming calamities. — Description from novelcodex.org