In Enemy Nations you can choose a race of that you'll be the leader - there's a great amount of them, mostly of course alien, but also the earthlings can be chosen. After this you land on a randomly created terrain with your landing ship. Your task is to conquer a planet for your race. Of course you're not alone, other races try the same. The game is basically a real-time strategy game, but with an important economic aspect, resource management is very important. The game has no campaign mode, all missions are stand-alone.