Mission 1: Among the Ruins
Create a Spawning Pool
Create a Hydralisk Den
Destroy the Terran Encampment
This mission is the introduction to the Zerg. It is similar in format to the Terran intro. The game will guide you through most of the level. Follow the instructions and learn how to use the Zerg Hive and to train troops. Use the Zerg Drones to create buildings.
Note that you cannot create Zerg units at will. You must have a Zerg Larvae available. Hives can only have up to three Larvae at any given time. You must wait for more Larvae to spawn before you can build more units.
Build a Spawning Pool by selecting a Drone and telling it to morph into a Spawning Pool. Note that all Zerg Buildings except the Hive must be built on the Creep. Have another Drone morph into a Hydralisk Den.
Mission 2: Egression
Bring the Chrysalis to the Beacon
Grab the Hunter Killers. These are hyper-powered Hydralisks that deal extra damage and have more hit points. Note that they cannot be replaced if they die; six is all you get. Bring them to your new base and begin setting up. Make sure to group your Sunken and Spore Colonies for maximum effectiveness. At the very least, pair a Sunken Colony with a Spore Colony so there are no holes in your defense.
Create as many Drones as you need to harvest resources quickly. Speed is not crucial for this mission, but it will allow you to work more efficiently. Use the Hunter Killers to destroy any Protoss forces in the local area. Be sure to bring them back to your base if they start taking heavy damage.
Build as many Zerglings and Hydralisks as you can. You will need at least 24 Zerglings and 12 Hydralisks (plus the Hunter Killers) to clear the map. Clear your way down to the main Protoss base in the southwest. There will be scattered forces along the way. Destroying them first makes assaulting the main base much easier. Target Photon Cannons first, then Protoss troops, then buildings. Destroy the base to complete the mission. Bring the Drone with the Chrysalis down to the beacon when have destroyed everything.
Mission 3: The New Dominion
Protect the Chrysalis
Eliminate the Terran presence
Immediately set up a defensive perimeter. The Terrans will be attacking with Marines, Firebats and Siege Tanks. Sunken and Spore Colonies will not be enough; you will need Mutalisks this time. Build a squad of 12 and keep them on hand to repel enemy assaults.
Create 12 Hydralisks, then send them and your Mutalisks to the north. You will find another resource cache, which you can put to use if your main cache is running low. Keep your Hydralisks here to guard your second base. Begin building a second squad of 12 Mutalisks. The Terran base is heavily fortified against a ground assault, hence the Mutalisks. Use them to decimate the Terrans. If you find your assault unsuccessful, create 12 Zerglings and 12 more Mutalisks. Run the Zerglings in to draw the fire away while your Mutalisks destroy any ground units that are giving you trouble. Destroying the last Terran building ends the mission.
Mission 4: Agent of the Swarm
Protect the Chrysalis until it is ready to hatch
Infest or Destroy Raynor’s Command Center
Quickly fortify your base with Sunken and Spore Colonies. The Terran forces will be coming in by Dropship, so be ready for them. Try and destroy the Dropships before they land. Hydralisks work well for this. The enemy will attempt to land on all sides, so your defense must be tight.
The most important element is defending the Chrysalis. Keep a squad of Hydralisks near it until it hatches. This will happen ten minutes into the mission. Start building two squads of Mutalisks and research Transportation for your Overlords.
Send your Mutalisks to the southeast. You will find another island with a large resource cache. Land some Drones here and start setting up. Send your Mutalisks to the far north, then have them fight their way east. This gives them easiest and most direct route to Raynor’s Command Center. Have your Mutalisks and any Hydralisks you can transport to the battlezone destroy the Terran Base. Target Missile Turrets and Marines first.
There are two ways to finish the mission. You can either destroy Raynor’s Command Center or Infest it with a Queen. Destroying it is easier since it allows you to skip building a Queen and you need to severely damage the Command Center to infest it anyway. Destroy the Command Center to end the mission faster.
Mission 5: The Amerigo
Bring Kerrigan to the Supercomputer
Group your units together and follow the path. This mission is identical in format to The Jacobs Installation. Be on the lookout for the same units and the same kinds of traps. Step on the beacon at the end of the path to reveal your target: the supercomputer.
TIP: Stop and rest if your units get badly damaged. The Zerglings are a write-off, but the Hunter Killers are essential. Have Kerrigan use her Cloak to hide herself if she takes too much fire.
Continue following the hall through the civilians, vultures and down to the southeast. Stop when you get to the gate. Cloak Kerrigan and send her in alone. There are several Goliaths here that are made much easier if Kerrigan destroys them while cloaked. Bring the rest of your units through when the Goliaths are destroyed.
Follow the path to the next gate. There are several side rooms along this corridor, but entering them is completely optional. Go through the gate at the far end. You will find some Marines shooting Zerglings in a pen. Kill the Marines and claim the Zerglings.
Resume following the path until you reach a gate that won’t open. Go north to find some Firebats and Marines. More Marines will arrive as you enter the room. Kill them all (don’t worry about your Zerglings.) You will find two beacons. Use the beacon on the right first; this will open all security doors. Use the other to be teleported to the next hallway.
Follow the corridor past the Ghosts (cloak Kerrigan and have her kill them) and to the far southwest end. The final room is heavily defended with automatic turrets and Marines. Destroy as many of them as you can, or simply have Kerrigan run for the beacon. Once she touches the beacon, the mission is complete.