The Noble Master Developer's Blog announces Demise of Nations is now available for Windows, OS X, and Linux as an early access deal after 2.5 years of development. This is set during the rise and fall of the Roman Empire and described as a mix of Civilization and Unity of Command "featuring deep game-play including research, city-building, trade and resource management." Here's more on the game:

In Demise of Nations a player commands his armies in one of the many ancient countries including the Roman Empire, the Greeks, Carthage and Sparta. From Rome to Celtic nations, one creates his own warring experience. Wage colossal wars solo, against the AI, or take on your gaming friends in cross-platform multiplayer games. Form alliances and fight co-op style with the AI and other players for ultimate victory. The game supports cross-platform multiplayer matches against players on PC, Mac and Linux.