(By the way, we don't mean the much-loved computer game, Civilization. This is a GedankenExperiment "What If" game.)
The purpose of the CivilizationGame is to understand ... civilization. The rules are that 1) you are immortal, 2) you are sent back in time to some historic period, like the Roman Republic or even the Stone Age, 3) before being sent back you have a period of time to research anything you like. The goal of the game is to figure out how to rebuild civilization as quickly as possible.
In order to play the CivilizationGame well, you need to know a lot about the subject. Not just technology, politics and history but also sociology, psychology, psychohistory, et cetera. Obviously, understanding civilization is crucial to winning the CivilizationGame. Not so obviously, one gains greater insight from playing this game than from trying to merely explain the history of civilization. Mere enumeration of facts impedes deep understanding of a subject. Even a ranking of causes of facts in order of importance is insufficient. To understand a domain, you have to have at least a feel for the possible alternatives. If you don't have that then you're just engaging in one long endless PostHocErgoPropterHoc argument.
To rebuild our civilization we would just need powder and physics. All the rest is not very well developed. For example in early XX century Europe there still was famine, but Europe had conquered had the rest of the world 5 centuries before, usually destroying other civilizations who rejected to pay taxes, just as the RomanEmpire did in the past.
How can we know that our civilization is so poor in other respects? Simply because it is advancing so fast and yet producing so little difference. For example medicine is ever improving, but it is really expensive and it doesn't really understand the human body. It is rather like Engineering applied to the human body. It simply doesn't fix anything.
This is spoken with a very poor idea of what life was like in the Roman Empire. Yes, countries still fight wars over similar causes. No, that doesn't mean that we still have no conception of human rights and accept casual infanticide. The existence of similarities and analogies between us is important, but it shouldn't blind you to the existence of differences.
The civilization game boils down to one thing that Richard Dawkins wouldn't necessarily say but is extrapolated as every "thing" - every nucleic acid, every fish, every idea, every person, every religion knows only one thing. That is to be. Unfortunatlely, to be means to make more, and to make more you have to use, and to use you have to own. It is the drive that makes indivduals lie, countries fight, and species die. We are somewhere between the first big bang and the next fizzle, but what is certain is that Roman empire or 21st Century Capitalism, dinosaurs or the New York Yankees, are all but temporary keepers of the title of world champion.