Command and Conquer 3 Walkthrough Scrin Mission 1, London

The first Scrin mission can be tough, but not with a little preparation. Begin the attack by selecting all your units and grouping them, then proceed to the east. Don't clear any of the buildings on the western side. Focus more on the southeastern corner. Clear everything, focusing on any GDI vehicles that come to attack you. The idea here is to clear an area for your base. The drone platform should be deployed just south of the tiberium field, and the surrounding area to the east should be cleared.

When you've finished all 15 buildings, the drone platform, with a small escort of gun walkers, will arrive. Move them to the spot south of the tiberium field and deploy the platform. Build first a pair of refineries, followed by a power plant and portal. When you've got the power plant, you can start making buzzer hives. Build three northeast of your base, east of the tiberium field. Keep them close together so that one does not have a longer range than the others. This will help to nullify GDI infantry attacks coming from that direction. Use your mobile forces to guard the south while you create multiple photon cannons for the southeast. The goal with the southeastern cannons is that they do not have the range to reach the bridge, causing it to be destroyed and forcing the GDI to occasionally send vehicles to an alternate attack route. Try to place them so they'll hit the GDI as they exit the bridge. Both your buzzer hives and photon cannons will need frequent repairs.

While you are building your base defenses, build a warp sphere and produce six gun walkers and two seekers. Send them to the northwest to eliminate the structure, along with the GDI infantry there. A dozen more gun walkers with an explorer should head to the north to secure the tiberium there. Again, once the explorer is deployed, build a trio of buzzer towers to hold off the GDI infantry. A second refinery is entirely up to you, but there is not that much tiberium in this location.

Taking out Big Ben quickly at this point will help to boom your economy while you produce seekers. First use gun walkers to mow down the infantry, then reinforce your walkers with more of their kind, along with some seekers. Focus fire on the building while the infantry aren't attacking, but you may be able to avoid interference all together if you attack from the middle-west of the landmark.

The extra income from the destruction of the landmark will help you to continue to produce seekers. Make about thirty, if you can, but at least come close to that mark to make this exceptionally easy. Don't neglect gun walkers, but you should have enough left over from your previous fights. Get them repaired, and, when you're ready, steamroll the GDI.

I found the southeastern bridge to be the best place for an attack. If you send your huge army over it, they'll destroy their first victims while they make their crossing. Once most units are across, start focusing fire on buildings and defensive structures. The army should be quite large enough to handle all of the defenses here, and destroy the construction yard. If you for some reason didn't have enough to eliminate the northern base as well, consider building a quick expansion to gather some more income.