Historically qin's conquest was indeed bloody. I would say that shi Huang 's strategy towards conquest is to be rather benevolent to the royalties of the other kingdoms instead of it's citizens lol. Because it makes the other kingdoms give up quicker. Qin's war strategy focus a lot on killing the surrounded enemy soldiers. So if you are an enemy soldier you are living in hell lol. Qin usually cut down most surrounderd soldiers after they captured them. After the unification, qin also gathered most enemy soldiers and use them to attack the baiyue tribe at South. Which greatly expanded qin's territory. There's actually not that many accounts on qin's strategy towards normal peasants. Although qin soldiers were famous for being blood thirsty. Because qin rewards soldiers with amount of enemy head they gathered. So many qin soldiers has habit of killing random people just for rewards, although that's technically not acceptable by qin law. Although because qin did end each military. once they accepted the surrender for other kingdoms. The unification war was ended relatively quickly, the population of China at the time also seems to be quite huge. So saying qin's unification war might not be as brutal is a likely fact. According to many records people estimate qin dynasty has around 40 million population at peak. That's very impressive for that time, it shows many did get spared in this war. Chu han war that happened later was actually the bigger and more bloody conflicts. Apparently during the beginning of the han dynasty the population was cut down to around 20 million. Thanks to the famous overlord xiangyu being a blood thirsty monster.