We all know how important macro is, but the most visceral and exciting parts of StarCraft (as both a player and spectator) come from micro in engagements. Commentators love to talk about army positioning. Stephano always seemed to make his units worth more than others with his army movement.
Over time, the community has invested a lot of thought here and layered heuristics and strategies around micro. These include ideas like “don’t attack into choke points,” “split your Marines against Banelings,” and “trigger Widow Mines with individual units.” A lot of this advice is generally correct, but there are exceptions and ways to over-apply these principles.
At its core, the idea of winning engagements is to hit them, don’t get hit. StarCraft is a game of numbers, and they don’t lie and in many ways lack the subtlety of real life. Damage is damage and should be applied liberally to enemies and avoided on one’s own army. Here’s how I see this applied in practice.
Always be shooting (except with Widow Mines)
Damage is damage, and you should hit them. Unlike Brood War, there is no high ground miss chance. Despite how much we talk about positioning, it is rarely worth it to miss taking shots for positioning. Thanks to the cooldown, you can kite and stagger movement to get positioning while taking the shots you need. It may not seem like much, but many engagements are won and lost based on the first volley (think about 2 Siege Tanks in siege mode firing at each other), but apply that at every point in an engagement.
Widow Mines happen to be a big exception here. Due to the cooldown, Mines can be more effectively used with good control. I myself lack the control to do anything fancy with them, so I just let them shoot early and let it be.
Arcs and flanks aren’t always better if everything is shooting.
Commentators love to point out how players will spread them armies to form arcs or separate their armies to flank. This sort of positioning is valuable because it exposes more of your army to fight, again on the principle that it lets you hit them. If you boil away the details, however, what really matters is how many units are firing on each side. If every unit on both sides is firing, the positioning is largely irrelevant: everyone is shooting away and doing damage.
The benefit comes when some of your opponent’s units are stuck behind and not a part of the engagement. That type of engagement is similar to ninjas attacking the martial arts hero one at a time: you’re hitting them with stuff while some of their units aren’t hitting you. For example, if you have your Marines in an arc around their ball of an equal number of Marines, you can imagine a few Marines in the middle waiting for their buddy in front of them to die so they can step up to fight. This is an effective engagement. If it’s all Marauders in the middle of their ball, however, everyone is involved at the same time, and the arc is less relevant and is just a good way to prevent escape.
Focus fire, but don’t over-focus
It’s better to kill 1 unit than to leave 2 at half health because you’re getting hit less. I think that should be obvious, but is often not really under our control given the large and chaotic nature of engagements. On the opposite end, however, you don’t want to overkill. If 20 Stalkers all focus 1 Marine at a time, they’re not hitting with roughly 75% of their shots. This typically, however, doesn’t happen. I believe even Siege Tanks have logic to prevent overkill.
It’s hard to control, but there is 1 notable case I should point out. Both Roaches and Hydralisks actually have melee attacks if they’re standing directly next to the unit they are attacking. It does the exact same damage, except the attack is immediate and not a projectile. The benefit of this is that it prevents overkill since your units won’t target and fire at units that current have deadly projectiles incoming. As such, it is worth it to stutter step Roaches up to melee range against, say, Marines and Marauders when possible.
Spread to minimize splash damage, clump to reduce surface area
When facing splash damage such as Banelings, Fungal Growth, Siege Tanks, EMP, Psionic Storm, or Colossi, you want your units spread out as much as possible to avoid getting hit. Conversely, against melee units and more generally, you want to clump to concentrate your army’s hitting power and reduce exposure to getting hit. As such, I think many great compositions mix these to exploit your opponent in different ways.
Conclusion
So those were a few of the examples I could think of based around this thinking. I know it doesn’t seem very sophisticated, but hit them, don’t get hit can pare away some fluff in micro and get to the core value of different engagements. Positioning in combat is key, but it isn’t intrinsically valuable: positioning is only important because of how it affects damage distribution.
Believe in the heuristics and advice on positioning: they’re usually right, but take the time to figure out when they’re wrong, too.
Great articles about engagements