Metro 2053: I Have an Enhancement System

[System + Apocalypse + Transmigration + Leveling Up] College student Xiao Jun wakes up after a car accident to find himself transmigrated to the Beijing subway thirty years after a nuclear explosion! Radiation monsters roam freely, and humanity struggles to survive in dark tunnels. Fortunately, he awakens an enhancement system, allowing him to become stronger by killing monsters! [Ding! Killed a mutated giant rat, Strength +1] [Ding! Unlocked weapon enhancement module, the rusty iron knife evolves into the Annihilation Longsword!] While others are still fighting for half a compressed biscuit, Xiao Jun has already crushed the head of a mutated centipede with one hand, smiling as he extends his hand to the survivors: "Don't be afraid, I'll take you back to the surface!" In the depths of darkness, a greater conspiracy is brewing... What truth does this apocalyptic subway hold?