Guerilla tactics are a common method of play, rather than a particular strategy (a series of systematic actions). Guerrilla tactics can be used at any stage of the match. It is also referred to as micro play, multitasking, cheesing, drops, over-committing, harassment, and a hit and run style of micro management.
When a player fails to engage the enemy successfully early on or in the middle of the match and their army, worker population, and building numbers are reduced, or when a player is performing slower than the enemy, the match will become an "asymmetrical war". This refers to the fact that one side has a clear advantage.
At this point, guerrilla tactics are most useful. The player using guerrilla tactics should focus on three very important aspects:
- Avoid open ground combat.
- Acquire and maintain a terrain advantage.
- Coordinate between bases.
Avoid open ground combat
The main philosophy, and first important aspect is to avoid open ground combat in order to prevent more army losses (in case of an asymmetrical war) or to gain time to get more ground control, population, and research completed. In exchange, the player will operate in small groups, making fast attacks to suppress enemy expansion and to get tactical objectives. One goal is to to split the enemy army into smaller groups. In some cases, the enemy will choose to handle one large army to try and over take your smaller groups.
This means that the enemy has to be harassed constantly until they start to lose ground control, army size, buildings, and resources, or just get demoralized (remember, human players can rage quit). The enemy will be forced to engage you all-in or deal with the constant harass and give you time to match his army size and composition for later.
Acquire and maintain a terrain advantage
The second important aspect of guerrilla tactics is the use of the terrain to your advantage. For example, making the access to your ground difficult to the enemy, or protecting and blocking tactical regions or bases on the map.
Terran and Protoss generally engage with the use of Dropships or Shuttles for their great mobility, as they can work in small and fast groups in air and/or ground.
In comparison, the Zerg are most guerrilla friendly because they have ground speed advantages (when upgraded), and cost less per unit. They also have the benefit of covering the ground with creep, blocking enemies from building on it. They can also use tunnels between bases to have better control of the map while on defense.
Coordinate between bases
Late game tactics
Once enough time has passed, the guerrilla War will evolve into a big scale war, or conventional (macro) war by having enough power to deal the enemy in his own territory.