The effectiveness of Infestors in ZvT

Many players may no longer remember the infestor of old, with its low damage, yet terrifyingly long eight second fungal growth, which reigned over ZvZ by locking up mutalisks. Looking to change this, Blizzard cut the duration of the ability in half, and compensated for it by buffing the damge. In doing so, They released a monster hungry for dominance in all of the matchups, not just ZvZ. 

Quickly paraded to popularity by streamers such as Destiny and Catz, the infestor, with its high damage output, along with the manuverability to be moved while burrowed and the versatility of infested terrans to draw seige tank fire and shoot air targets, this unit became the center of attention, specifically in ZvT. But why is this?

Before the dawn of the infestor, the main unit composition in the matchup was Zergling/Baneling/Mutalisk, where the mutalisks would try to catch tanks out of position, and the zerglings and banelings would focus on the marines. However, there were fundamental flaws with this unit composition, and strengths with the Infestors.

Using your opponent against them

To a certain degree, the composition relied on the enemy making mistakes. Mutalisks that were allowed to abuse high ground, likes the ramps that make up the main base on every map ever, would be able to pick off seige tanks with little fear of chasing marines, and seige tanks that are left open or lightly defended while marines are trying to bait an attack or clear creep tumors will be decimated in a timely manner by the Mutalisks.

However, eventually the Terran players will get better at not making the mistakes to leave tanks undefended, and mutalisks lose their efficiency. Clearly, this was a long, slow process, and it is still not a skill refined among lower league players. Therefore, mutalisks can rule in the games if the zerg player has the multitasking to harass during downtime, pick off reinforcements when the terran player moves out, and focus the tanks with your mutalisks during the fight. Although this can sound like a lot, using your APM efficiency when using mutalisks gives a much higher reward then infestors, though comes with a higher risk. Having your mutalisks get caught under a ball of stimmed marines will send them spiraling to the death, and you to an early GG.

Getting into late game

The late game composition. The two late game units for Zerg are obvious: Brood lords or Ultralisks. Now, either of these units, when worked in combination with the infestor in the hands of a skilled player can make a Terran wet themselves. And since the ghost nerfs, the Infestor has improved that much more in late game compositions. Mutalisks on the other hand, just don't fit the bill. If a player decides to build mutalisks in the midgame, they won't be good for the overall unit composition, only proving useful to counter the medivac drops that Terrans love to do in order to counter the slow moving broodlords. Infestors however, have great synergy with both the ultralisk and the Broodlord.

In coordination with Broodlords, infestors are a deadly and potent force. Due to the Broodlord's high range and attack power, the terran position will eventually crumble under the might of the combination fo zerg forces. So when the terran gets to this point, he will most likely choose one of the two options in the next minute or so: 

1. The terran will fall and drop your bases. at this point in the game, your main and your natural will most likely be mined out, but they will still hold important tech buildings like hives, spires, and evolution chambers, which would be devastating if lost. Also, since you're a zerg, you need lots of mining. However, due to infestors being able to 2 shot groups of marines with fungals, one at each base should make for easy clean up with drops with a queen and a group of zerglings.

2.  The terran will try to force something with vikings that can abuse their long range by sitting under marines, or by using cliffs. Although the brood lords will be able to hit the ground units backing up the vikings, it wont be cost effecient to lose your brrodlords, the most expensive Zerg unit, all for a few marines. And if the zerg player tries to back up the brood lords by retreating, the marines can easily stem, rush foward, and geet underneath them, meaning in a loss for you.

So what is the solution? infestors.  When the vikings come up to harass by trying to use cliffs or overhangs, the fungla range is still enough where you can fungal them. then have corruptors clean them up while chaining fungals. If you don't have an oppurtunity to get a good fungal, (and never ever put your infestors on the front lines in order to do so)  pull back your brood lords and try to bait an advance from the marines where they will lose covering fire from seige tanks, and then fungal the marines. If you feel extra daring, even neural parasite a thor. With the fungals on top of the marines, your brood lords can make short work of them out of range, and then the vikings will have no cover, letting your corruptors take care of them. Obviously this is an ideal situation, and never works perfectly, but in theory this is how to do apply it. 

Using your larva

The reliance of  zerglings in a mutalisk heavy composition to deal with marines can be devestating. Although zerglings, as everyone knows are the cheapest and quicket units in the game, they do have flaws, mainly by their fragility and their need to be replaced quickly, which can hog up larva needed for drones or late game units.

Although mutalisks are, without a doubt, the greatest tank killing unit in the game, their rely too heavily on harassment and not engaging in a straight up fight when you only have a few of them. And to actually reach the point where you have enough mutalisks to deal with marines (about 20 or more) can mean that many less drones or zerglings, whereas 5 infestors with two fungal growths each can do huge damage to a terran army by fungaling marines, or launching infested terrans to let your zerglings get in close range. In addition, infestors can help set up for awesome baneling hits, which will easily turn the tide of any battle. This makes the infestor a much better, more versatile unit then the mutalisk during big engagements with less units. 

Due to these flaws, the mutalisk soon fell out of favor with many Zerg pros, and those that chose to stick with the composition despite the newly forming meta were considered to be slow and behind the game. 

Although Infestors are not without faults of their own, mainly their dependence on a strong, gas-based economy. Mutalisks do have probably the best harass in the game, and once you reach a crticial amount of mutalisks with armor upgrades, they can destroy most amounts of missile turrets and marines trying to defend thewir helpless workers. However, despite these things, infestors have proven to be absolutely devestating against the Terran menace.

For the Swarm!