StarCraft/Zerg mission 1: Among the Ruins

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This one is really straightforward because it's more of a Zerg tutorial than an actual mission. Daggoth will tell you step by step how to build a Zerg base, but here are some key things to remember:

You start out with 12 Zerglings.

1. Drones become the structure that they build, so you must never use your last Drone to build something.
2. Overlords are equivalent to Supply Depots.
3. All Zerg units (except for one) are morphed at the Hatchery.
4. Zerg structures (except the Hatchery and Extractor) must always be placed on Creep, which originally begin from the Hatchery but can be extended with a Creep Colony.
5. A thing the game doesn't tell you right off the bat: you can use an enemy Zerg's Creep to build your own structures.

Have your forces block like this (sans the Zerglings).

After you've established yourself, Zasz will order you to destroy the Terran presence here. To start with, build 24 Zerglings (you start with 12) and 12 Hydralisks. This won't be enough, so be ready to build backup units; also, mutate your lone Creep Colony into a Sunken Colony so it can defend the Chrysalis in case of surprise attacks. Send your force up north and up the ramp at the northwestern corner of the map, and have them go east from here. You'll run into some defending units and a Starport, which your Zerglings shall destroy. Meanwhile, have the Hydralisks move to the ramp going down and physically block it so no Terran units can pass. Now, wait until you have a replenished force of 12 Hydralisks and 12 Zerglings, then move down the ramp and assault the main base (from this point on continuously build Hydralisks even if you don't think you need any more). Then, go south and destroy the Barracks, Turret, and any units that might be there to complete the mission.

The attack on the small outpost. Note that four of the Supply Depots up north were overlooked and not destroyed.