Birth of the RTS genre
Your base can build friendly units such as tanks, gun turrets and infantry. After you build a unit, you fly over a friendly base and pick up the built unit and then you can drop it anywhere in the field. While carrying the unit you can reprogram it with orders to give it a use once you let go.
Strategic points throghout the map give you the chance to launch assaults against the enemy base from a closer location. You take over the bases by making infantry and giving them a special order.
All this sound fimiliar? Yep, this game helped create the formula for modern RTS games.