Just started watching starting with season 2 first because Ceasar is chronologically first. It's fun good for people who are new to Roman history but it is flawed. The show states folk lore as facts in certain cases, it embellishes and take librities with things, such as:
Ceasar fighting Spartacus, far as I know ancient sources don't say anything about that. They were both alive at the same time though.
The republic elected two consuls, the show does say that briefly but they make it seem like there is only one.
The Roman legion fought in formation which was crucial to their success, but in the show they are as depicted as charging into 1vs1 combat.