As you might have well observed, Starcraft (both original and Brood War expansion) computer AI (that's artificial intelligence) players have a highly regimented building scheme. In fact, there's more to it than meets the eye. First, I will talk a little about their building schematic, then I will proceed to discuss anti-Terran tactics with the Zerg in...

Tactical Improvisations, vs. Computers Vol. 1

Okay. Computers, whether you believe it or not, KNOW where you are when the first start the game. Unlike us mortal players, they are calculating, processing streams of information. It was said best in "The Matrix": they can bend and break rules simply because they are not confined to the programming code of a human player.

What does this mean? Well, for one, computers, even if they play stupid and pretend to hunt you, have "vision" over the entire map. Don't believe me? Set up a single player free-for-all battle game, reveal your map with a cheat code ("black sheep wall") and watch. Sometimes, they don't even explore the board. They just go straight for your base. What were the odds of them finding your mineral site first? UNLIKELY...

Lastly, computers start the game with two basic objectives. These are defined by how advanced YOU as the player are by the time they are ready to execute phase one of their scheme. What I mean is that, if you are weaker than them after a given amount of time, usually 2-5 minutes, they will rush you and attack you. They can "sense" that you are weaker. In fact, they know you are. Furthermore, if you are stronger, they may even hold back and build a stronger force until they are sure they can take you. You know if you are doing better than them if they go off and make an expansion before they attack you. Anyway, onwards...

Zerg vs. Terran Ver 1.0.0

When we play zerg, what do two things do we fear most in the early game Terran arsenal? Firebats and tanks. Firebats do wicked damage to zerg, and tanks are inarguably apocalyptic. Here's a tactical improvisation that may just save your sorry arse from getting the crap burned outta you.

To execute: 1.) 2-3 Hatcheries and several reinforced sunken colonies for defense.
2.) Burrow ability
3.) Two large groups of zerg (usually 12-16 per group).
4.) Overlord Ventral Sac ability for unit transport.
5.) Zerg speed upgrade.
6.) Zerg carapace upgrade.

*The 's will make this trick much more successful.
Okay. This defense is geared towards a tank raid. Usually, tanks raids come well equipped with a supply of marines, firebats, and sometimes medics. Allright, here's how to hold these freaks off.
The first thing you must come to realize is the range of siege tanks. They can peg nearly any zerg unit and structure from outside its range of vision (especially late game). You must learn to locate the chokepoint of your base, find the cliff entry ways (stairs or ramps) or simply know the tank's line of sight.
The purpose of having multiple hatcheries will be to ensure a steady flow of zerglings into combat. Sunken colonies will reinforce your base if you have killed the tanks but the marines got through and your troops have been wiped out.
Get burrow. Once obtained, burrow a large group of zerglings either in the chokepoint, or just outside your base where you are certain the tanks will seige. If you have hydralisks, you may bring them up to the cliffs so they can fire down on unwary troops. The object here is to burrow your zerglings where the tanks will enter siege mode.
Get a second wave of zerglings. Keep them with your sunken colonies, when the raid comes, use the second wave of zerglings to defend your base and to draw the marines and firebats away from the tanks. Timing is everything. Once the marines enter your base, unborrow your zerglings and INSTANTLY have them assault the tanks. With 16 you can destroy them in minutes. You may see the computer try in vain to weave its marines back to the tanks. The tanks may even begin to unsiege themselves. This is okay. Most often, the sunken colonies will finish off the marines. Attack each tank one by one, dont fan out. This ensures their swift destruction. If you have any zerg from group two left, send them charging upwards toward the tanks and fleeing marines as the tanks unsiege. There's nothing more pathetic than an unsieged siege tank in the mornin'.
*Note: Ventral Sac dropping is helpful when large groups of tanks are attacking. It enables you to drop zerglings right into the tanks without them having time to react. Zerg carapace will help the zerg stay alive longer as they tear apart the siege mobiles. Lastly, zerg speed upgrade is invaluable when charging head on into tanks because otherwise youll be ground up like moving sausages. Remember that this trick is geared towards early game combat. And as always, the more zerg, the better.

CreepColony's Opinion: Comps are very predictable, so there's really no point in playing against them.