Core Contamination Spreads
The Objective
This one's simple -- eliminate all Core units and structures.
The Map
You'll start this mission in the lower-right corner. The enemy base is located in the center-left side of the map. Beware -- there is a hill in the left-center of the map that is very heavily defended by Core units and laser towers.
The Strategy
Units in the beginning of this map are few, so conserve them -- don't send them off to attack everything in sight. Build your base as normal, balancing your energy production and metal extraction. Use a few laser towers to bolster your defensive perimeter. Slowly expand your base, gaining metal resources and space to build while protecting structures with laser towers. A radar tower will give you early warning if enemy units are approaching, even if you haven't explored the territory.
As your units start to see action, they will become damaged. You can repair them with your Commander or any construction vehicle by selecting the "Repair" button from the orders menu, or by selecting your Commander, pressing the "R" key and then selecting the unit you wish to repair. The Commander will move toward it and immediately begin repairs. If you have many damaged units, you can select the unit you wish to do the repairing and then select Patrol (the "P" key). Click a point along the path of the damaged units, and the repairing unit will repair each damaged unit it encounters on its route.
Keep your eye out for enemy units attacking from along the right side and lower left of the map.