Mission 5: True Colors

Conditions for winning

• Destroy all enemy Structures
• Kill Duke
• Kill Fenix

Conditions for losing

• All your structures are destroyed

This mission starts out with a Lurker cutscene, and when it's over, start mining and send your Zergings and Hydralisks in one of the two directions right away. Sending them east cripples the Protoss base, making their attacks significantly weaker if they can, at all. Or, send them west to get rid of the Terran presence and nuclear strikes, Marines and Siege Tanks with other assorted units will not bother you.

Anyway, either attack down the east of west coast. Once you've decimated one side, the time will about run out, and build defense for the side that you didn't attack. Do not attempt to try to kill both sides, as it usually brings on attacks from BOTH sides, which you do not want.

Take over any resource spots available on the side you rampaged on, and use those positions to launch Hydralisk and Zergling attacks against the other side. This should create a pincer situation between your north base and your coastal base.

Continue attacking while you get to Guardians in the tech tree, and get a bunch of those. Keep pushing with attacks in groups, and you'll eventually win. This is easier to do if you kill the Terran and send forces against the Protoss, since they cannot nuke and get rid of large quantites of units and structures at a time.