You will have access to a crazy amount of resources in this mission, and you start with three hatcheries. You'll be able to easily realize the hording capabilities of the Zerg. A new item you can build (but don't need to) is the nydus canal. The two canals in your main base lead to the two other hatcheries near the beacons. The left leads to the northwest and the right leads to the southeast. Using these you can quickly build up your main base and get to the top of the tech tree quite rapidly. Keep your overlords on the beacons throughout the mission. Finally, you can build ultralisks on this mission. They're great to absorb damage and can deal quite a bit of their own. Now to the walkthrough.

Take kerrigan and the two hydralisks at your first base down to the nearby beacon. They'll do fine guarding it. Send one ultralisk to each of the other beacons via the nydus canals. When you're able later, reinforce these beacons with a few hydralisks (with upgraded range) to help take down the attackers. Now you should build up drones. All three hatcheries should be working to get you up to 12 drones on minerals at your main base. Once that's done, build an extractor and put three more drones on that duty. Get a spawning pool, evolution chamber and hydralisk den, then start building a total of 12 zerglings and six hydralisks. While they're building, set up some sunken colonies at the entrance to your main base and change the existing creep colony to a spore. Put another spore colony on the eastern border of that base also. Have all the military forces you created meet at the northwestern hatchery. There they can head to the east and attack the small Protoss outpost guarding the resources there. Now you have even more resources! Build another hatchery there and put four drones to gathering minerals and three on vespene. You'll be rolling in resources. You know what to do with them!

Get to the top of the tech tree and research away. You're going to need guardians and ultralisks for your first assault. Get up at least 10 guardians and four ultralisks with an escort of 24 zerglings and eight hydralisks. The Protoss base you should first attack is directly south of your main base. Some scourge would make excellent cheap scouts to scope out the base. Use the guardians and cautiously inch your way forward. You can take out the photon cannons and smear the reavers and dragoons without much trouble. As a matter of fact, with these ten guardians I didn't even have to bring in my ground forces. You can, once the reavers are gone and you're sure of it, just to speed up the destruction.

Now if you lost anything, replace it. This same force can finish the map. You can also build yet another expansion at the minerals of the base you just destroyed! This is wise as there's no guarantee something won't go wrong with the final battle. Research the overlord speed upgrade before you proceed to the next base so that you can detect dark templar. Leave the overlord in the back of your forces.

The final base is in the area in the screenshot - west of the southeastern beacon. It's not a very powerful base, but you may encounter many reavers and some dark templar. If you're slow enough you may even run into archons, huge powerful protoss creatures that can target air. If you see one, focus your guardians on it. Their power should never be ignored. Again, clear any reavers then move in your other forces. This won't be hard at all, and even if you fail you have access to so many resources you could even horde the enemy with mutalisks and guardians to finish them off.