Return to the Future: I Can Calculate the Rainstorm

Reverse: 1999

No System, transmigration, single male lead, some angst, a little power fantasy, comedy, with changes and cuts to the game's original story.

After years of severe depression, the protagonist finally can't take it anymore and dies by suicide, then transmigrates into the world of 9. The story begins with the Cosmic Overture, and he joins Laplace along the way. Later, he gains some of the Storm's power and begins traveling through different timelines.