Speedrunners Play Supporting Roles in the Game

Li Ruohuan traveled through time and became a supporting character in a game called Fantasy Island. The world will be destroyed if there is a bad ending. He wanted to use the knowledge of the game to pass the game quickly, but he met unexpected characters, a strange magic lecturer, two original protagonists, and the characters in the trailer of the new version of the game also appeared in advance. There is also a countdown to the crisis event that is approaching. How can Li Ruohuan avoid passing the game with a bad ending?