Why would he spoil his own manga? Yes it deviates from history, but this manga wasn't non-fiction in the first place. It's inspired by true events and obviously replicates a hell of a lot of the warring states period and Qin's pursuit to unify China. But to my knowledge, Yasuhisa Hara never said he was just going to tell the history play by play in manga form without adding his own plot. Just enjoy bro. The only thing you need to see where the series is going is the manga itself.

No, history won't change or should I say the outcome won't change, Qin will 100% unify China it has shown in the first chapter. Some people may die, some people may live (this will be different from history), but that's all. So you can say the event stays the same, but how it happens will change. Like the Death of the policy writer guy.

which points were changed completely to the original history of the warring states?