I Gained Power in a Post-Apocalyptic World and Became Unrivaled in the Real World

A brief description of the manhua I Gained Power in a Post-Apocalyptic World and Became Unrivaled in the Real World:

With his university entrance exams only a week away, Chin En should have been worrying about his future—not fighting for his life in a world overrun by zombies. Every night, he finds himself thrown into a terrifying Apocalyptic World, where hordes of zombies roam the ruins and survival comes at a brutal price. Hunger, wounds, exhaustion… no matter how badly he suffers, waking up always brings him back to the Real World. But something is terribly wrong. As his condition deteriorates in the Apocalyptic World, strange changes begin to manifest in his real body. The two worlds may not be as separate as he once believed. And if that’s true… what happens if he dies there?

Determined to survive, Chin En takes up arms and begins slaughtering zombies. Then, after defeating one of the monsters, he discovers something extraordinary—a mysterious green gem known as a Crystal Core. The moment he consumes it, his wounds miraculously heal, and an unknown power surges through his body. Now, Chin En must travel between two worlds every time he falls asleep—one where he struggles to pass his exams, and another where every waking moment is a fight for survival. With death lurking around every corner and the secrets connecting both worlds slowly coming to light, can Chin En survive the apocalypse… and still make it to his university entrance exams alive?