Below is a model of Starcraft. It is fairly detailed, but works reasonably well. In many ways, it is almost like playing Starcraft... The black structure ate the bottom is there to simulate the enemy using a Static Engine instead of the complex Dynamic Engine that models the player. The AI is set up to produce attack waves from time to time.
Thanks to Jacob Garbe for repairing this diagram!
A Minimal Starcraft
If the digram above is too complex have a look at this simpler version first:
The following patterns are present in StarCraft: