RTA Sousha wa Game Sekai kara Kaerenai

Our protagonist, the speedrunning emperor of "Another Verse," suddenly feels sleepy in the middle of practice. When he awakens, the familiar opening of "Another Verse" is playing right before his eyes!? In this godly environment where the body is moving better than usual, you have to speedrun! Clearing the game world faster than anyone! Abusing bugs to fight, the "fastest" Isekai fantasy!!

(Source: Kadokawa, translated)