It is a completely atypical RTS, Sure there are games that have factions that are different, but generally they are still bound to similar elements. Base Building for example. One factions bases WALK! I dont mean the buildings can move i mean the entire base walks around, you build stuff into the sides of it for unit production and weapons. It has an involved storyline, its big vs small, its got single player, a planet conquering mode, robots, AZTEC MAGIC! Its amazing and the only thing that killed it is it was part of Games For Windows Live, a service that ate every game that was put on it, and forced always online that harmed everything.
People have made mods for this game, a community supported it through the dark times. Save it for them and others that never go the chance to experience this!