Starcraft 2 - Gaining or Preventing Critical Mass

You may have heard of a concept called "critical mass" when talking about Starcraft 2 and its strategies and tactics. This term means "An amount or level needed for a specific result or new action to occur", but in Starcraft 2, is usually referring to when you have produced and accumulated a certain number of one unit type, such that the number of units becomes more dangerous than they are individually.

Typically, the following units can gain "critical mass":

• Marines (with Marauders)
• (Blink) Stalkers
• Siege Tanks
• Mutalisks
• Void Rays
• Carriers

What tends to happen in games is that once your opponent achieves these numbers, they become really hard to stop, unless you have been accumulating units directly against what he's been massing.  Even if you have a balanced army, with a certain amount of anti-air or etc, his critical mass will generally do more damage than you can absorb while killing his mass, OR that he can use his mobility, slow unstoppable advance, or range to destroy key structures, but yet you will have a hard time countering it or attacking into it.

I've played several 2v2 and 3v3 games where one person masses one of these units and pretty much walks over bases like they weren't there.  To counter this strategy, you must SCOUT OFTEN.
Massing is a poor strategy if you can build counters against those units in time.



The other game aspects I can mention are key to success in any game:

• Pressure your opponent with harassment or even trade units to keep numbers down
• Expand more often than your opponent
• Defend against his harassment better than he defends against yours.
• Force him to build other units than the ones he'd like to mass, to defend against your harassment

 I discourage massing, because unless you are truly pro with your micro, or unless you've heavily scouted and the opponent's aren't massing the counter-unit, small mistakes can cost you the game.  For example, while your mutas might be able to outmaneuver a pile of marines, if you happen to fly directly over them, stimmed marines can really deplete your Muta count, and the unit-trade of marine kills for muta losses is a poor one.