My Zerg Understanding

This hits some time around or a little before the barracks is finishing. If I scout it then a wall-in is great, but if not, I think attacking it with SCV's usually still does okay? I don't remember the last time a 6pool actually made it into my base. In general, not a big worry.

This hits at 6:30. I usually lose to it if I don't scout that there's no base there. But a double-thick wall generally holds, and you have plenty of time to set up the double thick wall. I like to put a CC in the wall to ensure that I have the econ advantage when his attack is done.

I have no idea when this hits, but it's usually around the same time or a little after the baneling bust. I usually scout the one-base and assume baneling bust, because in either case I get out some marauders and I'm fine against one-base. In general, zerg one-base play doesn't scare me a whole lot.

This is less common lately, but still a definite threat. This hits at around 10:00, and the hope is to hold you at two base trying to defend while the zerg expands all over the place.

-If I'm going bio, then holding off the mutas for a little while is pretty easy. I generally either get up a third base, or let turrets and reinforcement marines handle the mutas and just march out with what I have. Or for best results, get a third base while I move out with what I have. If the mutas are at my base he is undoubtedly trying to expand somewhere. Find it, and either kill it, or fake toward the expansion and then drop his main or natural. I need to kill an expansion, or some main base tech, or some drones. If I do none of these, I'm probably behind.

-If I'm going mech, then it's really important to get at least one thor out by the time the mutas show up. You can slow them down by threatening him with hellions, making him stop to attack your hellions instead of devouring your mineral line. Since you'll eventually want those thors at the front, you need a lot of turrets to defend your bases. Luckily, you tend to have extra minerals in a mech style anyway. If you have the one thor up you can defend the mutas (position it in the mineral line for mass repair in case of magic box mutas). If you have two or three up, you can take your third base. With mech you're not attacking for a very long time, but some hellion pressure helps to keep the base count from getting too crazy.

These are really common lately. Generally two-base infestor styles don't have a lot of banelings, I assume for lack of gas. I believe the timing is about the same as mutas, maybe a little later because he has to wait for pathogen glands.

-I used to think this shut down pure bio hard, but with a) more marauders, and b) splitting before the battle starts, not after, you can still do okay in a direct engagement. Obviously the direct engagement goes better with tanks and lots of medivacs. With pure bio then rather than a direct engagement, I prefer dropping against infestor styles. If he got the infestors on two base, then he's trying to take a third base now that he has them. One medivac toward the main, one medivac toward the third, and try to micro both of them while macro-ing and taking a third myself.

-Mech seems really, really strong against infestor styles. If I'm meching, he's probably roach infestor, rather than ling infestor. I can set up tanks in defensive positions and take a third base, and then push with three base worth of tanks, hellions, and two or three thors. It's very important to maintain knowledge of where his army is when I push, either by leading with hellions or by scanning. If I don't know where his army is, then I need to maintain detection so burrow roaches or infestors don't wreck my tanks. I'll often bring a couple SCV's and build some turrets just in case.

This is a more frequently forgotten possibility. In general nydus is gimmicky and cheesy, but it can take you by surprise. Nydus doesn't combine well with lings, since they unload so slowly and you'll be in the main where there's lots of buildings to constrict movement. So the usual choice is roaches. If he gets it off in your base you're not necessarily dead; mech fares worse, but if you go bio you can usually do alright. But obviously it's better if you just deny the worm from building. So if I see a lot of roaches out of my opponent, I just try to keep an eye on the minimap and vision of everywhere in my base.

This style seems really greedy. It didn't really exist much until the queen range buff, but now hellions just can't deny the creep and third base. Hellions can slow the creep, but the third comes down pretty much whenever he wants it. Typically I try to scout his base and see if he takes gas any time near when his pool goes down. If the pool finishes and gas still hasn't been taken, he's probably going for four queens and a quick three bases with lots of creep. It may be that this is perfectly safe, and I need to just take three bases myself and accept it, but I'm still hoping this style isn't safe. I typically get four barracks on one base and try to get up combat shield, marines, and a couple marauders, and see if I can't deny some creep and the third base.

-I've been playing mostly bio since the queen buff, so I don't really know how mech plays out against this particular threat. I imagine with mech you'd mass up enough hellions that you can deny the third base a little longer. ~8-10 hellions should be able to deny it, but that's more than you'd really want with a bio-heavy style.

This is the less greedy way to get up three-base zerg that I used to see pre-patch. I still move out with the bio force and push up to the creep, scan, and try to pick off a few tumors before I retreat back. If I do it well I can force a few banelings or zerglings that he didn't want to make and pull back. If I do it badly, he surround my bio force with speedlings and crushes it with banelings. I try to get up medivacs, stim, and combat shield before I engage this one, which means he gets up the third pretty safely. Then I push out, and I have three bases to attack. Push at the natural or third while I drop in the main, then pull back with the push if it looks like it's going to die and micro the drop seems most effective. If he goes for a super early third like this, then I think that I should also go early third base and mass upgrades.

I don't see a lot of three-base muta, since mutas are less common nowadays, and back when mutas were common, three-base play wasn't. The timing is about 12:00 or 13:00. Generally if he goes for three-base muta, then he wants to just get a few mutas, ~8-12 of them, and then switch to infestors and hive tech. He won't mass mutas, because mass mutas is a race against the Terran. He'd like to mass up 20-30 mutas before you can get large numbers of marines or a few Thors, and then kill you, but if he waits until he's on three bases before he starts massing them, you'll usually have the marines and thors necessary to kill it handily. So three-base muta is generally trying to stop drops, harass mineral line, and keep you under pressure while he gets up fourth or maybe even fifth bases. With two turrets per mineral line, I'm generally pretty safe. They might go kill add-ons or something, but at any given time another round of marines is about to pop from the barracks to push them away.

Three-base infestor has a lot more gas available to it, so there will probably be zerglings, banelings, and maybe roaches to supplement the infestors. With infestors, banelings, and three-base worth of zerglings or roaches.

-I generally find pure bio won't cut it in a direct engagement. Maybe if I were MarineKingPrime I could micro it well enough to trade decently. Otherwise, I can only drop with pure bio and wait for tanks to get out. With a really huge arc I can compete, for example camping in a big arc around a ramp.

-With mech I feel a lot more comfortable here. If he goes fast three-base I can probably get up a third base safely. I need to have the hellion count high enough to stop mass ling, but I'll want those hellions early to slow creep spread anyway, so I just have to make sure I don't lose them. Otherwise same as for two-base infestor, I need to maintain detection so roaches don't devour my tanks with burrow move.

These are generally accompanied by infestors, zerglings, and maybe banelings. Mass marines does not work, although having a few marines doesn't hurt. At least four or five barracks need to have tech lab in case ultralisk tech comes out. In terms of possible responses, tanks do alright, although they do more good in killing the baneling or infestor support than they do straight killing the ultralisks. Thors are very strong, although spreading them out a little against the ultralisk and baneling splash damage is important. The best thing about thors is not that they deal with ultralisks so extraordinarily well, but that they do okay against both brood lords and ultralisks in case of a tech switch. Banshees can help in a gimmicky way, but in general air units are deadweight.

Zerg has to play a funny guessing game with his brood lord army. If he builds too many brood lords, he gets killed by vikings. If he leaves too many as corruptors, marines or thors kill his brood lords from the ground. Obviously infestors help in both these scenarios. In cracking a brood lord/corruptor/infestor army, it's important to have a good standing army to make sure the broodlings or any zerglings running forward don't do all that much, and a lot of viking production; I tend to get 3 starports, all with reactor. Scan often to see if his infestor and/or brood lord count is high enough to stop a marine run-in. If not, go and kill. If he has the infestors but not many corruptors, spread your vikings into a huge arc, and attack in. Pull back from any infested terrans that get tossed down. Start massing thors against brood lords, not just to kill them, but also for the inevitable ultralisk tech switch.