I don't have any firm view (so no vote, I'm afraid), but I do have some rather disjointed thoughts.
My suspicion is that "turannos" is not going to mean much to people unless they're historians with some knowledge of the relevant period; on the other hand, it's a nice distinctive trademarkable word, which might work on combination with a more descriptive phrase or subtitle.
"A Game of Tyrants" ought to be sufficiently distinct to avoid attention from a certain other "A Game of..." franchise, but I don't know how litigious they are. Then again, "A Game of..." feels a bit odd to me as the name of a game.
An alternative, getting away from the explicit reference to tyrants, might be something based on "Polis", as being the setting that each player is trying to gain control of.