So, with the patch 1.3 infestors are being experimented with by a big group of zergs who never touched their stronger 1.2 self because it was not shiny and new.
My name is Dice, some of you may have watched my streaming, and some of you may have never heard of me, others have played me on the ladder and ran up against a bunch of infestors. I am known among my fans as an infestor zerg. My builds incorporate infestors seemlessly and use them instead of mutalisks in the mid game to great success. I want to help the zergs out there by giving many of the tips I've found with infestors in an organized and easy to understand fashion. there are alot more to the flesh-reavers than most of what you have seen in professional situations (most of them have horrible infestor control, due to a lack of practice).
Survival Tips
For those of you just starting to use these lovable little monstrocities you first should know the very basics about how to keep them alive.
1. Keep them on a separate hotkey.
Advanced version: + Show Spoiler +
this hotkey should be a comfortable distance from the Fungal growth hotkey and preferably you should be able to position your hand so that you can go quickly back and forth between the hotkey and the fungal growth hotkey rapidly, I use 3 and F with my 3 pressed with my left middle finger and the F key with my left index finger.
2. Do not keep them near a ball of units. Infestors are horrible with pathing (as bad to sc2 pathing as dragoons were for sc1 pathing).
Advanced version: + Show Spoiler +
They should be kept extended in the front by a good margin, in order to fungal and remove themselves pre engagement, or off to the side and back some, in order to not be visible to ghosts, and armies and have easy paths in and out of the battle without messing up any concaves or becoming trapped.
3. Never leave them unattended if they are vulnerable, this means keeping them with your army when it is idle, but distanced from the army when it is on the move
Advanced version: + Show Spoiler +
Put them next to your hatches when you are macroing, this provides a few functions: they won't be sniped without you looking, they can be used as emergency detection if needed, they can protect vs drops, and your queen will not be lonely. then move them back to where they belong when no longer macroing.
4. Always cast from max range, This includes using the radius of the fungal as added range.
Advanced version: + Show Spoiler +
Units like the infestor turn around faster if yuo shift queue a perpendicular movement after the cast, and then as soon as the unit starts to turn, tell it to retreat, this makes the infestor spin faster than it would normally, allowing you avoid being hit (as much) and much more likely keep the infestor alive.
5. Have Burrow Researched. Even if the Infestor is not moving when burrowed consistantly having burrow allows a few more escape options if you somehow let the infestor get chased or caught out of position.
Spellcasting and General Tips
1. Smart cast hinders the speed of your fungal growth casts unless queued from a distance.
Advanced version: + Show Spoiler +
using the advanced tip from survival tip 1. alternating rapidly from infestor hotkey, fungal hotkey, click. allows the infestor/infestor group to ignore smart cast and repeatedly cast more accurate fungals, this is only true if you get very fast at it, though your fungals are always more accurate. also, queuing multiple spells with a group of infestors is typically bad and should be used almost never, it makes them suffer the full backswing animation adding a quarter second to their recovery before they can move, which will add up greatly over a infestors life.
2. Increase fungal radius whenever possible by targetting corners of many units instead of covering a few. It is possible to increase the size of a fungal growth to three thors wide. This takes familiarity with the size of all units radii and knowing exactly where they become vulnerable in their circle. this works with air units, though significantly less (you can only add half the width of a supply depot to the radius vs air units)
3. Always lead flying units slightly below them in order to hit them.
Advanced version: + Show Spoiler +
It also helps to mentally realize you will have to be moving your cursor to where the units will be by the time your cursor makes it to the unit will be flying to, but again slightly below them. For instance against mutalisks you will have to know the mutas will not be where they currently are by the time your fungal cursor makes it to that spot, so predict their movement in order to maximize the amount of mutalisks fungal'd.
4. Fungal growth as a damage spell mid battle is much less effective than fungal growth as a damage spell leading up to and during the engagement of the battle. During battle fungal is merely a roach targetting every unit (or a hydralisk vs armored) which is much less effective than having a couple roach volleys on every unit by the time the battle begins and preventing the opposing side from having a concave until yours is set up. This requires you having your infestors ahead of your army before an engagement and you being able to sneak barely within range of sight in order to fungal.
5. Siege tanks are not a counter to properly controlled infestors. You can use the enhanced range and radius from survival tip 4 and casting tip 2 in order to cast fungal on sieged tanks without being in sight range of their tanks though if spotted you only take a SINGLE shot which keeps the infestor alive. This allows infestors to harrass tank lines risk free, and if they move units out in order to spot for the tanks, fungal those and kill them with mutalisks/corruptors/hydras/zerglings in order to continue the harrassment. this requires practice and a careful eye.
6. Learn your own handspeed and exactly how many units you can make/larva injects/creep tumor spreads you can do in the timeframe of a single fungal, and DO IT. Odds are if harrassing with infestors you should be out of the way and able to do a bit of macro and come back to the infestor to refungal EVERY TIME. this is the key to making infestor bases strategies work, and the reason that your macro should be better than going mutalisks. while mutas require constant care while in use, and have downtime when not in use to macro, Infestors are kind of the opposite, you can macro through use, but have to take care of them when not in use.
7. Learn that you can defend more bases with infestors than you can with mutalisks, and use this to gain a production, flanking, and economic advantage in every game. This also requires great overlord spread and alot of map vision, so don't be afraid to send 10-14 lings and overlords around the map to burrow, and spot in case of any attack at any time. This means hotkeying the locations of your infestors with F keys in order to defend any drop or harrassment at any time.
8. Use Fungal to kill observers whenever you see them. 1 fungal + 1 queen hydra or mutalisk will kill an observer.
Hope you enjoy these few tips and definitely think about these when trying to improve your infestor play in games. Enjoy the most versatile caster in the game.