People die all the time in the most boring way (illnesses, accidents), battles are not that epic, no monsters or great heros, overall knowledge of the people are very shallow, etc.
Think a mashup of AC and forgotten city (a Roman game with a time loop that focuses on talking to the locals).
It presents a primitive material reality, but also the culture and supernatural beliefs.
It doesn't have to be without monsters, it just have to portray them according to beliefs of people of that time, and not according to our modern interpretation, or modern appeal. It could be an opportunity to also document ancient societies, culture, mythical beliefs too.
An addition. Also make a survival mode, where you are not just sightseeing safely, but also have to survive whatever is happening.