StarCraft/Rushing

Overview
Rushing is generally considered a low-level strategy, primarily because advanced players are often prepared to resist a rush and because rushing causes the player to fall behind on their economy at the beginning of the game, which would ultimately result in an enemy victory if the rush is not successful.

Rushing does not have to be totally successful--taking out an enemy base completely--to be rewarding. If a handful of rushing units can dispatch multiple enemy workers, then the enemy economy will suddenly be in an even worse condition than that of the rushing player. In order to succeed, however, rushes must be conducted swiftly, either by quickly obtaining a handful of low-level units at the expense of economy and technology, or by quickly obtaining a handful of high-level units at the expense of both economy and all other military. Should the enemy defenses complete before the rush, the rush would either fail or be called off, and in each situation the rushing player would be at a loss.

In order to properly resist an enemy attack, it is best to have either one defensive structure protecting the base and mining operations or a handful of units to repulse an enemy attack. The former is cheaper, because defenses are inherently cheaper than normal units, but is also inflexible, especially when the enemy scouts can report what structures a player is building and the enemy can thus choose to expand instead of obtaining military units. In other words, the enemy would be forced to obtain units for each of your units, while the enemy would likely create one expansion for about every three defensive structures, because the enemy would never fear an attack by your static defense (they DON'T MOVE).

Zergling Rush
Try to play against your opponent in a small one-on-one map that you know very well. Send your four drones to start mining minerals and order your overlord to your opponent's base (to spy on him; no race starts out with anything to attack air early; by they time a Terran player gets Marines you should have your Zerglings). Hatch 5 more drones (for a total of 9, the maximum supply availible (1 Overlord (8) + 1 Hatchery (1))) as soon as you can and order those to mine too.
 * Variation: Order one Drone to build an Extractor so that your supply goes down to 8. Hatch a drone, cancel the Extractor, and order the drone to mine again. This way, you have 10 drones with only 9 supply.

When you reach 200 minerals, order a drone to morph into a Spawning Pool. At 100 more, hatch an Overlord (it takes less time to build than a Spawning Pool and you won't need it until the Pool is done). On another note, if the player has amassed at least 450 minerals, he can build a second Hatchery, for if the rush fails.
 * Variation: Do the Extractor trick again for another 10th Drone.
 * Another variation: Since Zerg buildings can be built on any creep (including that of another player), send a Drone to your opponent's base and order it to morph to a Creep Colony. Once this is done (probably after the Zerglings hatch), morph the Creep Colony into a Sunken Colony. Obviously, this only works if your opponent is also Zerg and pays no attention to his/her own base.

Once both (the Spawning Pool and Overlord) are done, hatch 6 Zerglings (two for each larva) and rush to your opponent. If you are lucky, you will catch your opponent totally unprepared. Try to kill as many of his workers as possible and you will be guaranteed a win. If your zergling rush fails, you will fall behind in mining resources. Most experienced players know about this rush and can defend well against it so be careful of whom you use this strategy against.

Counters:
 * Terran - Build an early bunker near your resources and place one/some marine(s) inside (repair it during the attack with an/some SCV(s), or just get plenty of Marines early. Since they have range, some marines can attack while others move backward. You can also put them behind buildings so that the Zerglings must run around the buildings, giving you extra time to fire.
 * Protoss - Build two gateways and try to have two zealots come out by the time the Zerglings arrive. Alternatively, build a Forge and some Photon Cannons, although this is not recommended.
 * Zerg - Do the same thing. Because your opponent is rushing you, you have extra time to build defense (your opponent must make units and have them run to your base). You can also get a Sunken Colony to protect your base, although some players do not recommend this as it is too defensive.

Lurker Rush
Lurkers are fun to use against Terran and Protoss because of their lack of mobile detectors in early mid-games and therefore can be used to secure vital locations early on. This is very similar to the Dark Templar rush (Protoss) except it is slightly lower on the tech tree but much more costly in gas.

Counters:
 * Terran - A Marine-filled Bunker with a nearby Missile Turret placed near your resources or a choke point. If you do not have an Engineering Bay (required for the Missle Turret), you can get an Academy (which is good for the Marines & Medics and Firebat strategies) and then add a Comsat Station to your Command Center.
 * Protoss - About two Photon Cannons placed near your resources or a choke point (if there is one) and/or Observers.
 * Zerg - An overlord; this strategy really doesn't work against Zerg.

Mutalisk Rush
Mutalisks are fast flying zerg units and can be really annoying if used properly. They are good to use against Zerg and Protoss, and maybe against Terran too. They require a lot of gas though so build an early extractor followed by another hatchery and a spawning pool. Upgrade the hatchery to a lair. Don't forget to make more drones and overlords in the meantime. Build defenses if you have to, but not too much. After lair is done, make a spire. After the spire is done, make 6 mutalisks and rush them to the enemy base. If there are no anti-air defenses near the enemy's resources, then whoopee! Kill all his workers. You can also kill his army if his troops can't attack air.

Counters:
 * Terran - A marine-filled bunker near your resources. A large marine army with medic support is also nice. Upgrade U-238 shells and stimpacks. The stimpack upgrade is also highly useful here and can of course be used liberally thanks to the medics nearby.  A fair supply of missile turrets are probably the best defense going for Terrans though.
 * Protoss - Photon cannons near your resources. Maybe early corsairs and also high templars and an archon.
 * Zerg - You own Mutalisks, and Scourge.

Zealot Rush
During the first few minutes of the game, rush into the enemy's base with at least 4 Zealots. If your forces have an obvious superiority over the enemy, destroy their base as a whole. If not, try disrupting their mining operation as much as possible to cripple your enemies' abilities to retaliate in the long run. This is often done by setting the zealots to move straight to the resource collection area to attack the resource gatherers, after running by and typically taking nominal damage from enemy forces concentrated in a front area of the base. A common mistake of amateurs is to try to run the zealots through in attack-response mode, so that any engagement by a frontal defense at the base distracts the zealots into battling the defending units, leaving the resource gatherers to continue their work unimpeded.

Dark Templar Rush
This tactic involves a rush of Dark Templar, typically 1-3 for an early game edge. Works very well against Terran; also works very well against Protoss if the enemy does not yet have any cannons, though even a single cannon, allowing other combat troops to attack, often effectively neutralizes a dark templar rush; it is often somewhat useful against Zerg players, because the few and extremely slow Overlords they have in the early game can not provide detection everywhere. This strategy is high-risk because it requires the user to ignore defense and early game units, and tech straight towards Dark Templars, if there is to be a realistic chance of catching a Protoss or Terran opponent before they have detection capabilities. Dark Templar rushes are frequently used in high level competetive play, and even if it fails to properly cripple an opponent, it might prevent an early attack. Just a couple of these can easily wipe out an entire mineral line or take out a single Turret or Comsat Station to further avoid detection without loss.


 * Defense &mdash; Another good strategy is just to build defense by building a whole bunch of Photon Cannons. These defenses structures are the best of any race in the game and should be used to help protect yourself while you mine and create a massive army.

Because Dark Templars cannot be seen unless in the range of a detector, they are quite useful to use before your opponent(s) get detection. However, because they are also quite high up in the tech tree (Nexus>Gateway>Cybernetics Core>Citadel of Adun>Templar Archives), it is recommended that you build some sort of defense (Cannons, Zealots, Dragoons, etc.) while teching up to Dark Templars. An early assimilator is also recommended because they cost 100 gas (and 125 minerals) each. There are too many variations of the strategy to give a specific build order. However, when doing a dark templar rush in a low mineral map, it is best to hide the templar archives and the citadel of adun in order to make the dark templars a surprise attack. Also keep in mind that if your enemy is Zerg, this rush is useless as Overlords are detectors and are required for the Zerg race.

Static Defense Rush
This tactic involves building Photon Cannons just near the enemy's base, so that (if properly positioned) they can attack the opponent. Usually, the Photon Cannons are placed so that they can kill enemy workers attempting to gather resources. Anywhere between one and three Photon Cannons can thus cripple the enemy at a relatively low cost. The popularity of Cannon rushes means opponents are often prepared to prevent them, which requires rushers to find new variatns of the strategy. Both Zerg and Terran have defensive structures much less suited for rushing. Sometimes, a player who rushes with Photon Cannons forgets to defend his own base, leaving him vulnerable to an attack.

This strategy takes a lot of speed and luck. In some Starcraft maps, such as the popular Big Game Hunters or Korhal of Ceres, the mineral fields of certain starting positions contain a pocketed area behind the mineral field with a single 2-matrix-wide entrance, small enough that a Probe may seal itself in by constructing a Pylon at the entrance of the pocket. It may then warp in one or two Photon Cannons as a Forge is completed back at the base. The cannons' positions make them impossible to reach without first destroying the Pylon, which has a combined total of 600 points in shields and structure. This usually occurs in the first three minutes of the game, so the aggressor is almost always left completely defenseless at home. Most of the time, however, the defender has not had enough time to set up proper unit production, and if the cannons are warped in without the Pylon being destroyed quickly, the nexus of the defender is at risk of being destroyed, which may prevent the player from mining any more minerals (if they do not have the 400 minerals required for a second Nexus), essentially taking them permanently out of the game. Counters to this include the construction of Sunken Colonies or Bunkers near the mining areas.