Hint :
Hint: Excellent defense (Eurasian Dynasty):
Research Lasers, Heavy Lasers, Ion Cannons and Rocket Launchers as far as you can. Then, research Heavy Towers. Surround your base with walls, and at certain intervals, place Heavy Towers. At the top of the Tower place a Heavy Laser and place a normal Laser on top of it. On the left side place an Ion Cannon and on the right side place a Rocket Launcher. The Ion Cannon will freeze any unit that gets near and disable its shields, allowing the lasers to destroy it easily. The Rocket Launcher will destroy anything foolish enough to attack from the air. Also use the highest level shield for your structure. For added defense use Artillery. Also do not forget to use Radar emplacements to detect stealth units.

Hint: Excellent Defense (United Civilized States):
Research AA Plasma Cannons, Plasma Cannons, and Heavy Plasma Cannons as far as they will go. Then, research Fortresses. If your base is in an open area, use some walls to protect it. Place a Fortress into an easily defensible location near your base, such as a valley between two cliffs or a bridgehead. Then, place a Heavy Plasma Cannon, two AA Plasma Cannons, and a normal Plasma Cannon on the fortress and use the highest level shield available. The Heavy Plasma Cannon and the normal Plasma Cannon should eradicate any ground forces and the AA Plasma Cannons will take care of air units. Also, the Fortress has enough armor to withstand a lot of heavy attacks without dying. For added defense use Artillery. Also be sure to place an SDI when fighting against the ED!

Hint: Excellent Defense (Lunar Corporation):
Research Heavy Electro Cannons, AA Rocket Launchers, and Sonic Cannons as high as they will go, along with the Heavy Defense building. Now line the area you want to defend with Laser Walls and place a single Guardian defense structure. First, place two Heavy Electro Cannons down. Next, put two Sonic Cannons on top of these. Next to this, place two Nests each with an AA Rocket Launcher on top. Also, the LC has the best shields in the game so be sure to use them. For added defense, put some artillery in the area. Also be sure to place an SDI when fighting against the ED!