Original War looks like your standard RTS until you sit down and play it. It is similar to Myth, in that you often do not get new characters or units through a level, but are made to keep each unit around and use them in the next level. Characters also have RPG like stats that you improve as you progress, making each units value increase as you play through the game.
Without ruining too much, the story revolves around preventing a crisis in present day by travelling back in time to move resources. This resources must be moved from a place enemy factions have access to them in the present day to a location accessible only to your faction in present day. So off you go into the past to move resources so that in the future, your faction will have them where they need them.