Here's a tatic
Put 1 ion cannon in the front middle, upgrade it 1 time, and start putting bunkers around it. Get the ion cannon to lvl 3, then research the economic thing. get an economic building, and put it in the back column, behind your cannon. Upgrade the economic building. Build 2 more cannons in the same row as your 1st cannon, next to the fortifications. Research the repairing thing. Take the bunker behind your 1st turret away, and replace with a repair thing. Start upgrading your bunkers...and the rest you can do yourself =P
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