Command and Conquer 3 Walkthrough GDI Mission 13, Cologne

You begin this mission with a tough team, backed by a commando. Keep them together at all times and they will be quite safe. Head first for the scouting location, using attack move to keep the commando on his toes. It would be a wise move to use the buildings to garrison when you encounter an intimidating number of Nod. Remember that you are scouting not destroying the base. Head to the east toward the engineers when done.

Try to get there as fast as possible, then cleave your way to the north toward the power plant you must capture. Don't be a dummy and walk on the tiberium field. Keep your engineers as safe as possible as well, remember they're slower than your other units. Capture the base and build a war factory and tech center. A second harvester will help improve your income rate. During this construction, capture the reinforcement bay to the west and build an expansion at the rich blue tiberium fields south of your base. Don't leave it completely unguarded from air attacks. When your tech center is built, start producing mammoth tanks and zone troopers. When you have 4-6 mammoth tanks start producing some APCs to load with snipers (3-4) and missile squadrons (10). Keep the juggernauts for your main assault to help take out base defenses. Build a couple extra power plants, or ensure that your current ones are upgraded to facilitate the addition of a few extra sonic emitters later. Lastly, get an engineer loaded into an APC.

When you've amassed a large enough force, push your mammoths first across the bridge (“roll over them!”) and establish a small area of control there, then rush in everything else just behind and unload an engineer right next to the power plant there. He will capture it, turning on the sonic emitters nearby. With that, this becomes much easier. Kill any devastator warships near the base and try to goad the enemy into coming out right into the path of your sonic emitters. When it looks like they've thrown most of what they've got at you, head straight for your objective and destroy it.