Surviving the Apocalypse? But I Thought I Was Playing a Game

[Terminal illness + doomsday game + sci-fi apocalypse + pay-to-win survival + game invasion + infinite worlds] Su Xian is terminally ill and has only three months to live when he receives a mysterious VR headset. When he puts it on, he enters a game world that perfectly recreates reality. And here, zombies roam freely and the apocalypse has arrived. The game mission is simple: survive for 30 days. But the game is terrifyingly real. The zombies' snarls, the feel of flesh and blood, the despair of facing death... Everything is far too vivid to be virtual. Even stranger, the "enhancement crystals" he earns by killing zombies in the game can ease his real-life pain. The strength he gains in the game also makes his body stronger in reality! To stay alive, Su Xian has no choice but to fight to grow stronger in the game. But this game is a real money pit: saving costs money, reviving costs money, and even a rusty sword requires a first-time purchase! Just as he thinks it's merely a realistic, pay-to-play survival game, he gradually discovers something else: The "teammate" he meets in the game is actually his former boss. Does she play the game too, or is she just an NPC? And outside his window in the real world, things seem to be changing in strange ways every time he enters the game... Am I really just playing a game?