Survive and Level Up!

Main Character, who was a normal person has woken up in a transformed earth. He has no idea what happened. He learned that everyone was the same and zombie apocalypse has been rampant already on earth.

Now, he must fight to survive. Before that, he will learn that he got a level up system where he can gain levels, attributes and skills to get stronger. Just like a regular MMORPG.

Eventually, he will find out what really happened.