Pro StarCraft II Explained: Fundamentals

  • Blizzard Entertainment

StarCraft II can seem overwhelming at first glance, but once you get used to some key aspects of the game, you’ll be able to follow even the most complex professional games. If you’ve had trouble following a professional match, this article will go over some basics on what to expect.


Terran Army.jpg

Typically, you’ll see Terran players focus on either bio units from the Barracks, or mech units from the Factory. When watching a bio-focused player, watch for quick, impactful movement from their Marines and Marauders. They’ll typically be supported by a complement of Medivacs, so you’ll see the player move them out of harm’s way while still healing the bio forces on the ground. They’ll also use Medivacs to drop small harassment forces into the enemy’s base to distract or deal economic damage while the main force moves elsewhere. Additionally, Liberators may be used to keep the enemy from charging in or flanking the main Terran army. They may combine some mech units into their main force, though they’ll mainly be used to support and supplement their bio units.

Mech builds are an entirely different style of play. They’re less mobile in general, but they provide excellent hit-and-run damage in the early game followed by strong, difficult-to-penetrate defenses in the late game. Early in the game, they’ll focus on getting out some Hellions early to deal heavy damage to basic units like Zealots, Zerglings, and workers while kiting to avoid taking damage. Later, they’ll create some Cyclones for potent long-distance harassment. Their late game will center around Siege Tanks, Vikings, and Widow Mines. Using these in conjunction with some bio units, area lockdown is their specialty. Watch for positioning changes as Siege Tanks move deliberately and carefully to new locations and the Terran tries to bait the enemy into moving into areas threatened by the Siege Tanks, Liberators in Defender mode, or Widow Mines.


Protoss Army.jpg

The Protoss are similar to Terran in that they have two main production buildings and focus on two overarching strategies. Gateway units are the bulk of most early- and mid-game armies. A mixture of Zealots, Stalkers, Sentries, and Adepts can synergize well to create a powerful, potent force with a strong ability to make smart plays with the Blink, Force Field, Guardian Shield, and Psionic Transfer abilities. With some Immortals and Disruptors from the Robotics Facility, it’s easy to make a difficult army to punch through. While not as mobile as some Terran or Zerg compositions, it’s able to dominate straightforward fights.

The alternative is to focus more on air units from the Stargate. This usually revolves around Phoenixes and Void Rays to harass and disrupt enemy bases. Phoenixes in particular are highly mobile and can join the main army to disable key units in the middle of battle. This will lead to a late game army with a large focus on Tempests, which dominate the field while the rest of the army soaks the damage from enemy attacks. Regardless of build, you’ll see Immortals and Colossi produced to deal with specific enemy units. We’ll cover that more in the Counters section below.

Zerg Army.jpg

The primary focus for Zerg is map control and aggression. A Zerg player excels when they operate on more bases, have control and vision of most of the battlefield, and react appropriately to their enemy’s strategy. In the early game, the Zerg can take an advantage by harassing the enemy with Zerglings, especially after researching Metabolic Boost, which gives Zerglings increased movement speed. With effective Creep spread, adding Queens and Roaches into the mix can make for a very fast and effective early-game force. Once mid game hits, it’s important for the Zerg player to pick a direction with their military. It’s likely he or she will evolve their Roaches into Ravagers and add Ultralisks or Lurkers to deal with large ground armies. Banelings are also a potent addition to deal with ground armies, so watch out for large impacts to swing entire fights.

If the opponent decides to focus on flying units, Zerg players may opt to focus on Corruptors, Mutalisks, and Hydralisks instead. If this is the route the Zerg player takes, it’s likely that in the late game they’ll evolve some of their Corruptors into Brood Lords for some very effective siege capabilities. Regardless of whether the Zerg player goes for a ground or air force, it’s likely you’ll see Infestors whenever the enemy has large, clumped up armies or the map has easily exploited choke points.


One of the earliest things you’ll see players do in each game is send a unit to the enemy’s base to see what they’re up to. Protoss and Terran players will typically try to build a wall of structures to keep enemy units out, but if they don’t build it fast enough, then the enemy can still get in and see everything. Also, building a wall doesn’t stop early-game units like Reapers and Overlords from bypassing the wall and getting a look around.

The goal of scouting is to see what buildings the opponent has made and what their current army composition is. If the enemy has invested a lot of resources into expanding into two more bases and hasn’t made any military units, it’s an easy call to send all army units to punish them for not having any defense. If a Zerg player infiltrates a Terran base and see multiple Barracks early on with no Factories or Starports, they can figure out that quick aggression from biological units is coming, and they need to prepare.

Alternately, they can also glean information from things that are missing. If a player shows up to a Terran base and they don’t have a Barracks anywhere, they can deduce that the Terran is doing something sneaky like a proxy, which we’ll talk about later. Scouting that can give them time to return to base to defend immediately. The best players can even calculate how much Vespene Gas their opponent has collected to determine what tech options the enemy can afford. Most commonly, however, a good scout will give a player information on what units the enemy is focusing on. Since every unit has its own strengths and weaknesses, knowing the enemy’s unit composition allows the player to make the most effective units to combat them.


An important gameplay mechanic to keep in mind while watching professional StarCraft II is the idea of counters. Certain military units are more or less effective against other types of units. For example, Roaches are Armored units, so they’re very strong against basic ground units like Zealots, Marines, and Zerglings, which all deal reduced damage to Armored units . But if the opponent starts building a large air force or ground units that are strong against Armored units like Roaches, such as Immortals or Siege Tanks, then the Zerg player needs to respond to that information. He or she will need to produce fewer Roaches and shift their focus toward creating units that have an advantage against what the enemy shows in their military composition.

In a professional game, the player knows the most common military compositions that their opponent is likely to build. It’s safe to build basic units in the early game, but by the mid and late game, it’s critically important that they scout out their enemy and figure out what they’re making. Information is fundamental in any strategy in StarCraft II, so it’s not uncommon to see small forces or single units sacrificed to see exactly what the enemy is up to.

When there is a surprise from the enemy, you’ll likely see a player slowly shift strategy or completely abandon their current build for a new focus on different structures and units, depending on how extreme the surprise is. For example, if a Zerg player focuses on Zerglings, Roaches, and Ravagers against a primarily Gateway based Protoss army, but the Protoss player has multiple undiscovered Stargates producing Phoenixes and Void Rays, that’s going to be an extreme surprise for the Zerg. All of their ground units are now useless as they can’t attack air units. They’ll need to immediately drop resources into static defenses such as Spore Crawlers, a Spire to get air units of their own, and possibly Hydralisks as well. It’s important to note when a player discovers new information so you can see how they react and change their strategy.


Cheese isn’t a standard practice in professional play, but it does happen relatively often. The basic idea of a cheese strategy is to destroy or cripple the opponent early with an unexpected and risky strategy. If a cheese succeeds, the offending player usually gains a significant advantage they can exploit early on, or they may even cause the opponent to concede the game. If a cheese fails, however, it’s very likely to put the attacking player significantly behind. Many times, this disadvantage puts them in an irrecoverable position.

One of the most popular cheeses is placing a production building like a Gateway or a Barracks close to the enemy’s base at the beginning of the game and start churning out units. This is called a proxy. Another effective cheese is the Protoss cannon rush, in which the Protoss player builds a Forge instead of a Gateway first, sneaks a Probe into the enemy’s base and builds a Pylon in the fog of war nearby. They then start creating Photon Cannons closer and closer to the enemy’s mineral line. If allowed to set up a large field of cannons, it can be impossible to recover from so early in the game.

At any given time in a game, a player can focus on spending resources to build up their economy, build up their military, or upgrade their units and structures. Professional players will generally try and invest in the most effective balance of all three of these aspects of macro throughout the game, but these cheesy plays forego economy and technology to put the entire game on the line with fast, all-in military investments. Watch for these plays to end catastrophically for one player or the other.

These are just some basics of things to look out for in a pro game. For some more detailed aspects of the game on a professional level, check out our observer panel, micro, and macro articles.