Answer: Shi Huangdi's success diminished because of his treatment of oppositors, in particular proponents of Confucianism. He is said to have burned book and buried scholars alive.
Shi Huangdi (259 BC - 210BC) was the founder of the Qin dynasty and the first emperor of a unified China. His self-invented title of "emperor" (as opposed to previous "kings") would continue to be used by Chinese rulers for the next two thousand years.
During his reigns, China greatly expanded its size. He enacted major economic and political reforms aimed at the standarization of the diverse Chinese practices of different regions. He is also said to have banned and burned many books and excuted scholars, particularly adherents to Confucianism. He joined several state walls into the Great Wall of China and built a city-sized mausoleum guarded by the Terracota Army.