Harassing your opponent’s workers can be an effective strategy in SC2 games. Successful harassing will slow down your opponent’s macro, giving yourself time to continue building up and going in for the kill. Here are a few harassing techniques:

Air-To-Land Harassment

Mutalisks, banshees, and void rays can all be used to knock out some of your opponents workers. The advantage of these aircraft are they are very fast. A successful harassment does not necessarily mean you kill all the workers- even killing just 6-8 of them is helpful, especially if you are able to get your units out of harm’s way when he sends in units that can attack your aircraft.

Transport Harassment

If your opponent does not have many defenses near his workers and not too many troops near his workers, you can use a transport to drop units, kill the workers, and then fly away to safety when his main army arrives.

Cloaked Units

Using cloaked units is generally the most effective way of killing all of your opponent’s workers. For Terran, this generally would be cloaked banshees (though technically you could use ghosts too) and dark templars for Protoss.

The effectiveness of cloaked harassment largely depends on your opponent’s detection capabilities. Cloaked harassment can often work well against Terran, since many players rely too much on the scanner sweep to detect cloaked units. When he does the scan, simply move your units away as fast as possible. Chances are he doesn’t have enough energy to sustain continuous scans.

Cloaked harassment can work well against zerg if your opponent doesn’t have any overseers. However, upon a cloaked rush, your opponent will likely morph one, so your harassment will be able to work as long as the overseer is in the cocoon. This still can be enough time to kill all of his workers if you have enough units.

Protoss have good detection capabilities since many players use photon cannons alot and the observer is a easy, quick unit to build. However, if your opponent does not have a robotics facility since they are heavy into void rays, you can quickly kill any photon cannon near the base (they generally will not have enough) and then continue to harass your opponent and may even be able to say gg.

Each SC2 race has its own strengths and weaknesses. Here is a brief rundown of the positives and negatives of the Terran, Zerg, and Protoss. If you have any other ideas you’d like to add, please comment on the forum:

Terran:

Pros:

* Easiest race to play well. Campaign will help newbies familiarize with the race. Employing an MMM rush is one of the easier ways to get quick wins on battle.net
* Tanks, tanks, tanks. They are great for defense and they outrange opponent’s defensive units.
* Relatively small amount of micro is needed. Not much spellcasting is needed to be effective with this race.
* An expansion with a planetary fortress/missile turrets can defend against most small attacks (have your SCVs repair the planetary fortress while your opponent attacks it).
* Orbital Command scanner makes scouting easy for the lazy. Mules are great to get minerals quick.
* Can wall off initial base to defend against very early rushes.

Cons:

* Harder to move troops across the map. Cannot warp them in like Protoss or use a Nydux Network like Zerg.
* Ravens are the costliest/hardest mobile detector to make.
* Vulnerable to early game rushes (zerglings or zealots).

Zerg

Pros:

* Easiest race which to expand. Hatcheries are cheaper (only 300 minerals versus 400 for Command Center/Nexus)
* Provided you have sufficient hatcheries, you can instantly spawn a huge army to replace the one that is currently fighting in a battle.
* Lots of rush possibilities- zerglings, mutas, or roaches.
* Many interesting counter possibilities to the other races.
* Overlords/overseers makes scouting/control of map easier.

Cons:

* Very micro-intensive race. Queens/infestors are important units and are primarily spellcasters.
* Heavy reliance on small units make these armies vulnerable to splash damage. High templars and several tanks can wreak havoc.
* Small range for most units. Only units that can outrange most defensive units are brood lords and they are very late in the game/slow.

Protoss:

Pros:

* Strongest units of any race. Armies are generally less vulnerable to splash damage.
* Warpgates and a pylon allow an instant warp-in of army anywhere on the map.
* Observers are cheap/easy detectors and great scouts.
* Many rush possibilities- zealot or void ray. Both can work even against good opponents.
* Photon cannons work against both air and ground attacks. This makes setting up defense the easiest of any races- don’t have to guess if opponent will come with ground or air.
* One probe can warp in as many buildings as it wants at once.

Cons:

* Expanding can be cumbersome and expensive. Nexus is 400 minerals plus takes a good amount of time. Then have to build a lot of probes. In contrast, hatcheries are cheaper and quicker. Terran have the advantage of drawing down a few mules from other bases to quickly gather minerals from an expansion.
* Can be overwhelmed in early game. Units/buildings are expensive and take awhile, so an error in early game can be deadly.
* Land units are vulnerable to air attacks. Only the stalker can attack air units (besides archons, but those are rarely used). In contrast, Terran have marines/thors and Zerg has hydras/queens.

A void ray rush is an effective early-to-midgame rush by the Protoss.

How it’s done:

Teching up to void rays is fairly quickly. All one needs is to go gateway, cybernetics core, and then stargate.

When doing a void ray rush, it is advisable to not have set build order, since you may need to respond to an early game rush by your opponent. For example, if your opponent send in zerglings, zealots, or marauders, you’ll need to setup defenses/pump out zealots to defend against their rush.

Thus, scouting is very important when doing a void ray rush. Detect if you’re going to get rushed yourself before getting your void rays ready. Also, find out if a void ray rush would be effective; if your opponent is stocked with anti-air units, focus on a different strategy to defeat your opponent.

How to defend against it:

Defeating a void ray rush generally involves having plenty of mobile anti-air units. While anti-air defenses are great, do not rely too heavily on this since the void rays are very quick and a skillful player can avoid them. Furthermore, the void ray beam gets stronger the longer the unit is locked-on a target, so void rays can take down defenses quickly.

Terran:

It is fairly easy for Terran to defeat void ray rushes; both marines and vikings make great counters. If a a Terran player is doing a MMM build, he or she can quickly switch to pumping out vikings instead of medivacs to take down the void rays. An advantage of the vikings is they also outrange the void rays. Basically, as long as you don’t overbuild tanks/marauders, you should defeat your opponent quite handily.

Zerg:

Zerg can often find themselves in trouble against a void ray rush. Many zerg players have heavy roach/zergling builds, which are defenseless against void rays. Queens are great at defending your workers and can cancel out a void ray on a 1-1 basis (which is good tradeoff in terms of resources since it’s 150 minerals instead of 250 minerals/150 gas). However, most players do not want to overly invest in queens since they are very slow and are generally bad at offense because of that.

Hydras/corrupters are the best counters to void rays that are offensively useful, but they are also midgame units and expensive. Thus, with zerg, it’s important to scout a void ray rush quickly and get a ton of hydras ready. Once you defeat the void ray rush, it’s generally rather easy to use your hydras to counterattack your opponent and seal the deal.

Protoss:

Protoss can have a difficult time against a void ray rush if they over-invested in zealots/immortals. If you do a factory build, be sure to pump out an observer against a fellow Protoss opponent. If you see your opponent is doing a void ray build, quickly switch to stalkers, andi f you can, phoenixes.

Your early rush failed and left you behind in macro. Perhaps you made a micro-related blunder when attacking your opponent and are now behind. Or perhaps your opponent has an extra expansion or two on you and you are behind at the macro level.

Your first thought may be to panic, and this emotional response is right in the sense that you do need to do something. However, mindlessly doing a last ditch attack is probably the worst thing you could do. Take a deep breath and figure out a strategy for how to come back.

Step One: Stay Alive

The first step when you are behind is to make sure you don’t get finished off. While this of course depends on the circumstances of the game, figure out how much you should invest in defenses. If your opponent launches an attack on you and fails, this may help you get back to even. Do some scouting to see if you think your opponent will attack and where he might attack. If aggression seems likely, invest in defenses to stay alive and hopefully counter-cripple your opponent.

Step Two: Figure Out Your Best Strategy To Gamble On

After doing your best to stay alive, figure out the way you think you may win. Perhaps your opponent is over-investing in land-to-land units and you should throw a last ditch effort into building a lot of air units that can attack land.

If you think your opponent is turtling, gamble that he won’t launch an attack soon and expand quickly. Sure, if you are wrong and he attacks you, you may lose. However, you are behind currently and won’t win unless you do something risky. By expanding quickly, you may get yourself a macro advantage in about 5 minutes time and can turn the tables on your opponent.

When you are behind, you can’t expect to do a standard strategy and beat your opponent. You will likely need to gamble one on strategy to take avantage of a mistake your opponent hopefully makes. It may be pursuing an aggressive expansionary strategy if your opponent is too hesitant to attack you, an air-based assault if he is too focused on land units, or perhaps a cloaked/stealth assault if your opponent is ill-equipped with detectors. Either way, you’ll likely need to gamble on a strategy and leave yourself exposed someway and just hope your opponent makes a mistake.

A standard Terran attack is the use of marines, marauders, and sometimes medivacs (depending on how late the player decides to wait until he attacks). This attack can be incredibly effective against players who do not properly counter the attack.

To do a MMM rush, the Terran player will typically wall off his base. He will then build units with the Barracks that walled off his base and build another 2-3 barracks. These will constantly produce marines/marauders until he decides it’s time to attack. The addition of medivacs will take time due to having to add a factory/starport, but the medivacs can be produces fairly quickly with the reactor add-on.

Countering a MMM rush depends on your race:

Terran: To counter MMM, you can simply do MMM yourself. However, the best counter would be to employ some tanks and vikings (if they have medivacs).

Zerg: The key to fending off a MMM rush is to build zergling/banelings instead of roaches. MMM will destroy roaches all things being equal since marauders get an attack bonus against armored units (roaches are armored). If you see they are coming at you, a good move is to put your banelings out front and then burrow them. Then, as the Terran player comes out, unburrow them and immediately attack them. This way your opponent cannot destroy the banelings before they do the suicide damage. After destroying some of your opponent’s army with banelings, use hydralisks to take out the Medivacs and zerglings to pick off the rest of their army.

Protoss: A variety of approaches can work with Protoss. First, if your opponent does not have tanks, Photon cannons work well. However, do not build too many of these since tanks can outrange these units. If it is later in the game, the High Templar’s psistorm is effective. Otherwise, charged zealots work well, as do immortals and Colossi. Just make sure you do not overbuild on buildings and have plenty of units to counter the MMM build.