SCP. The Foundation universe. Anomalies contained.
When Incident 5000 broke out, the protagonist was just an ordinary person. But as he was about to be shot, he made a wish.
As a result, anomalies vanished from the world. All the organizations dealing with anomalies had never existed either, but that was only what it seemed.
Over the next two months, more than a thousand SCP objects would gradually appear in this world.
With no organizations left to deal with anomalies, only the protagonist could stop it all. So he had to save the world 81 times in two months.
If he failed, the world would be destroyed.