One drawback for some players will be the fact that Dark Reign does not have varying difficulty levels. This is somewhat ameliorated by the fact that in order to progress to the next mission for either combatant you need only complete the previous mission as one side or the other. Power is used to energize your buildings, including defensive structures and your radar display. Water is the currency of the game. You collect it and sell it to gain money you need to build units and structures.
Water is scarce though.
Only pure water can be collected and sold. There are only a few sources of pure water on each map, making holding these locations important. You build transports that travel between your water supplies and your off world water export facility. After four trips to the well a wandering merchant will stop and pick up a load of water and pay you in the cash you need. You can also choose to sell water before a full load is gathered, though you pay a monetary penalty since the merchants don't like to stop for less.