We All Transmigrated, Are You Sure This Isn't the Ultraman Universe?

The protagonist of this story has no love interest, no love interest, no love interest. Important things need to be said three times.

Many people die in accidents and are given a choice between two options.

First, accept death and wait for their souls to dissipate.

Second, enter a game, clear every level, and earn the chance to return to the day before they died.

Game Stage One: Help the game world survive the wave of mutations.

Players: Fewer than ten thousand of us have to fight ten billion mutated creatures?

Game Stage Two: Help the game world survive the giant beast wave.

Players: We have to fight Gomora? Red King? Golza?

Game Stage Three: Help the game world survive an alien invasion.

Players: What the hell, even the Mefilas are here, and you still say this isn't the Ultraman universe!

Game Stage Four: Help the game world survive the stellar extinction crisis.

Players: Forget it, let's just let everything be destroyed...