Let's be honest, this story is good and interesting. He got the OP power but because his level was not enough, he had to level up until it was.
The moment he was trapped also made everything complicated for him, but it could be the best and fastest way to become powerful.
Worldbuilding is quite good, a mix of real world, tower world, and post apocalypse. I wonder if there's another universe besides Earth? Because Aerith always says 'Other Worlds'. I hope you'll explain it later in the story.