Terran Bunkers

This sort of strategy should be a worry to players very early in the game, and at expansion towns.

When attacking the enemy, use this method while the enemy is distracted or when the enemy doesn't have any units to stop it. Rather than sending in 4 Marines, send with them an SCV and Bunker your way into their town. You can start building them out of view of the normal paths into the village, then leap frog Bunkers closer and closer to the enemy town until you're building Bunkers inside it. Combine with Siege Tanks for even more effectiveness.

The best defense against this is regular patrols outside your towns, making sure the enemy is not setting up around them. Catch the Bunkers before they are completed along with killing any SCVs in the area.

This preventive watch must also be used to prevent the Protoss enemies from setting up Shield Batteries and Photon Cannons around your town.

The SCV finds the edge of the Creep and starts to build a Bunker. As you can see the enemy had a Spawning Pool, so they should have put Zerglings Patrolling the area. 2 Zerglings could easily kill this SCV before the Bunker was completed.

Once the first Bunker was completed, another is built close enough to cover the first one. The enemy transforms their Creep Colony into a Sunken Colony.

Marines are placed in the Bunker. The Sunken Colony completes and attacks the Bunker, while the Marines return fire.

The SCV completes the second Bunker and rushes to repair the first Bunker as it is being attacked. The enemy hoards Zerglings in reserve, which in this case is a bad idea. Had the Zerglings charged, this setup would have easily been destroyed.

The Sunken Colony is easily destroyed with no Zergling Support, combined with repairing the Bunker as it is being attacked. The Spawning Pool starts to take damage. In this case the enemy built their Spawning Pool too close to the edge of the creep. Had they placed their Spawning Pool right next to the Hatchery it would have been out of range of the Bunkers.

The Spawning Pool is destroyed, requiring the enemy to build another. (They should have started building another Spawning Pool as soon as they noticed the Bunker in range of it.) Another Bunker is built closer to the enemy town as the creep recedes.

That Bunker is completed and another one is built further up to the right to attack the Drones Mining Gas. If the Gas can be halted, the enemy cannot make Hydralisks.

That Bunker prevents the enemy from building another Extractor. Now they can only build Zerglings.

In another game, the first Bunker is placed next to the Gas mine. With an Extractor already completed the enemy should already have a few Zerglings scouting around or perhaps an Overlord or two which should easily spot this attempt.

The Bunker is completed and sits defenseless with no Marines in it, while the Marines walk the distance of the map to reach the Bunker. This gives the enemy ample time to detect the empty Bunker and destroy it.

The enemy notices the Bunker (Especially when it starts killing their Drones) and attempts to rush it with all their Drones. This is a very bad reaction. A lot of Drones will have great difficulty damaging a Bunker full of Marines, especially with SCVs around to repair it while it is being attacked. Zerglings also can be seen on the mini-map returning to deal with the attack. In this situation, this was also a poor decision. If the enemy has all these Bunkers in your town, you can be sure that they have no defense at their home base. If the Zerglings would have continued on their attack to the Terran home base, it would have surely been destroyed.

Drones should be kept mining as long as possible, moving them off of the Gas mine and on to Minerals. If 350 Minerals were built up, they could be used to build another Hatchery at another safe location.

The Zerglings return, only to be slaughtered.

The second completed Bunker by the Minerals insures that the Terrans are in control, especially with 2 SCVs repairing the Bunker while it is being attacked.

You should worry about this strategy on maps where the enemy knows where you are, such as 1on1 maps, 2on2 games, anytime where you are sure an enemy is in the location. If the enemy has to find you, this strategy won't be as effective.

This strategy is easiest to do against the Zerg because the Creep gives advanced warning as to where the Zerg towns are. The ends of the Creep are generally out of the line of sight for the Zerg buildings. That is why it is important to have troops scout around the edges of the town to prevent building.

Zerg players start out with an Overlord. Rather than using the first Overlord to find the enemy town you may want to keep it scouting around your town (to prevent such strategy as this) until a second Overlord is available for scouting. The Overlord should spot anyone building Bunkers around your down, then you can use Drones or Zerglings to kill the SCV building the Bunker.

If the enemy is building Bunkers in your town, they almost assuredly do not have any protecting their own town. A small group of 4-6+ Zerglings sent to the enemy town should totally destroy it. This will most likely prevent the enemy from building further Bunkers into your town or delay their offensive.

This strategy relies on destroying the Zerg ability to mine Gas and Minerals. By scouting around the Minerals and Gas, you should be able to find the Bunkers before they are completed. Particular care should be taken to avoid losing Gas as it is needed to build Hydralisks.

Kill the SCVs! SCVs are instrumental to this strategy. Rather than attacking the Bunker, attack the SCVs which repair the Bunkers and build more Bunkers. This will force the enemy to build more SCVs and send them down to your town where a few Zerglings can intercept them along the way. The enemy depends on these SCVs to keep the Bunkering Offensive alive.

Build a Sunken Colony by the Minerals and Gas. It will extend the Creep and fire on Bunker builders.

Build a group of Hydralisks. A group of Hydralisks can destroy the Bunkers. Do not send them in one at a time, but rather horde them, and then send in a large group once you have it. Destroy the SCVs first so they cannot repair the Bunkers.

Build your Spawning Pool very close to the Hatchery to make sure it is out of range of the Bunkers. The same should be done with the Hydralisk Den. Use a Creep Colony to extend the Creep so the enemy must build further away from key buildings.

Protoss and Terran players are also vulnerable to this strategy, to a lesser degree. Zerg players rely on Gas to build Hydralisks and advance up the Tech tree because Hydralisks in force are the best unit to destroy these Bunkers. Terrans, however can use Marines which require Minerals only. It is a lot harder for the enemy to build groups of Bunkers around the Minerals to cover them all, without you noticing them. The same is the case with the Protoss which need only Zealots which require Minerals only also. Both Protoss and Terran players should however take care that the same thing doesn't happen to them. A few Zealots or Marines Patrolling around the area should prevent anyone from building Bunkers.

Even if this strategy is prevented at the main town, it can still be used on all expansion towns later on in the game. As you advance up the tech tree it will be easier to destroy offensive Bunkering.