Ironclad, but the dungeon is in Hell difficulty.

In the year 7375 of the Star Calendar, the arrival of the Sudden Chaos was imminent.
Even though Yu Tianyi knew what was going to happen, he was powerless to resist the overwhelming tide of the times.
Just when he had begun to give up and accept his fate, the cheat code that was activated after traveling more than a thousand years finally arrived. However, the beginning of the game was the timeline of Luofu's fall and Huanlong's success.
"You haven't even settled things in the real world, and you're asking me to save the world?"
Having lurked in Luofu for decades, controlling hundreds of millions of living beings, and turning the entire Immortal Ship Alliance into its main arena, Huanlong...
The locust swarm successfully swept across the galaxy, defeating the gods and preventing the birth of any 'god' for tens of thousands of years.
Awakened anew by the Temple of Order, bringing everything to a state of perfect, mechanical efficiency, the Heavenly Dao 'Taiyi' that dominates the universe...
The 'branches' are reversed from the moment of destruction, the timeline is reversed, leading all realms toward the primordial god of the end, the 'Last King'.
The locust plague apocalypse, the order of heaven, the end of time reversal... each challenge is incredibly difficult. Fortunately, this cheat is quite powerful; leveling up by defeating monsters is standard practice, and the rewards for completing the levels are generous.
Unbeknownst to him, he had already ascended to the position of 'god,' looking down upon the world.
However, it seems that this is just the beginning.