I Give the Qin Dynasty a Golden Finger

He transmigrates as a fangshi and is hauled to the execution ground by Qin Shi Huang from the start. Just then, the System activates. Completing missions lets him exchange rewards for modern technology. Ying Zheng sneers. "You claim this can yield a thousand jin per mu. If you fail, you'll be torn apart by chariots." Chu Nan calmly produces hybrid rice, and the Qin granaries overflow. He then presents papermaking, gunpowder, and steelmaking, sending the Qin Dynasty's tech tree soaring. Ying Zheng: "My dear subject, the elixir of immortality..." Chu Nan silently exchanges his points for a human cryogenic pod. Wait, why is Your Majesty climbing into it himself?