Easiest way to win level 12: Use one of the command centers and place it right next to the air blocker. Build a few collectors and nullify it before the creep comes. Then return it to orbit and use mass air support at your pleasure.
Miner + light carrier = OLBITERATION. Good for EVERY infestation map. Not only will you get tons of energy, but your miners will destroy those pesky spores! When you have 10 or so miner spawners, just go for the light carriers. Their autoguns make them great against infestation. For the final level, just build 1 Annihilator straight away. You have exactly enough money for it. Don't even worry about anything else. Eventually you can get enough energy to build a reactor and then build more from there. Vote this up so others can see!
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