How do I get the "Zergling Rush" achievement in StarCraft 2?

I'm trying to get a lot of the battle.net achievements, but some of them seem quite difficult.

Specifically, "Zergling Rush" the 20 zerglings in 255 seconds achievement

From gaming McKay

• It varies between the players themselves as to whether or not rushing is "cheese" or not. A popular (or if not popular, at least viable) zerg rushing build (on Steppes of War, for instance) is 6 pool.

  I'm not sure if they are trying to encourage so-called "cheese" builds, but to get that achievement, you definitely have to do some non-standard build order (and if you want to call that cheese, then by all means).

  McKay : I'm merely calling it a cheese build, because it isn't sustainable. [Many](http://gaming.stackexchange.com/questions/359/what-build-order-should-i-use-for-zerg-in-starcraft-2/363#363) would call a 10 pool a rush, and it would definitely hurt economically. But a 8 pool? 6 pool? That's even rougher.
  From Raven Dreamer

• I do believe that it's not so much to promote cheese builds as just to reward a player for doing something really really really hard.

  It is very unlikely that anyone, once earning this achievement, will think to themselves, "Hey, I will now do this for every single game I play ever!"

  Rather, they'll switch to more reliable tactics after it.

  From Justin L.

• I pulled it off by doing a 14 hatch, 15 pool and then rushed queens and zerglings. I did manage to make 20 by the 255 second mark.

  With a 6 pool build order you should hit 20 zerglings at 4:05. Put your first 6 on minerals, morph pool asap. Leave the remaining 5. Morph overlord at 100 minerals. Spam zerglings as your larva comes up.

  McKay : Maybe you have better micro than I do, but I couldn't pull that off.

  McKay : Your second idea probably would work, sadly, I can't try that again. The achievement won't pop up.

  tzenes : Did you do it and it didn't pop?

  McKay : Yeah, last night I tried specifically that. It took like 4 or 5 times trying, because I always made a small mistake (like forgetting to have enough overlords or something), but even when I executed your 14 hatch 15 pool method as good as I can given my micro abilities [which aren't that bad?] I still didn't get it in time.

  McKay : I didn't try your 6 pool thing. It was added after I earned the achievement? I can't try it again, because I won't earn the achievement again.

  tzenes : watch the replay its 4:15

  Davy8 : Do you have a replay of the 14hatch 15pool? You said you rushed queens and lings but even with building the hatch right next to my main and overall decent timing queens didn't pop until 4:35. I think a couple seconds could be shaved but I don't think any more than 10-15 secs. I also tried without the queens. Pool and hatch finished at 3:43 for me. Max let's say that was down to 3:30. With 24 sec for lings to pop and 15 sec for larva pop, the latest larvae would have to be at 3:51. Assuming it got caught at the end of cycle (not sure how the timing is affected when you're at 3)[continued]

  Davy8 : you'd at most get 2 larvae from each hatch for 4 more total, and 4 when the 2nd hatch finishes, so 8 larvae = 16 lings. Unless the achievement is to get 20 started and not finished? That I could maybe with absolutely perfect timing.

  tzenes : @Davy8 this was a long time ago, so I don't have the replay anymore. I could try to get another one, when I have some time

  Davy8 : @tzenes np. I generally agree with almost everything you say here about SC2 but this particularly seemed impossible to me. I'm hoping that it is true because that means there's something big I'm missing that I could learn. Maybe you were measuring real time and not gametime?

  tzenes : @Davy8 I think everything I did was in game. I know I did a replay with 6 pool which I talk about in the comments and I had specific timings on. I may have written the 14hatch 15 pool from memory though
  From tzenes

• Here's what I finally got to work:

  • 8 Pool
  • 7 Overlord
  • As soon as pool completes:
  • Queen
  • Zerglings x 3
  • As soon as queen spawns, spawn larvae on the hatchery
  • When money isn't a problem anymore, kill a drone for the extra 1 supply for 2 zerglings
  • Keep building zerglings until the achievement pops up.

  In retrospect, I probably shouldn't have built that 8th drone. He probably just barely pulled his weight before the time limit, and I would have rather started the spawning pool that much sooner, which would make it 7 Pool, 6 Overlord

  Michael Herold : I'm not familiar with the shorthand used for build orders. Could you explain what "8 Pool" and "7 Overlord" mean?

  Matthew : @Michael: "8 Pool" means "After I hit 8/10 supply, build a spawning pool". This will bring you down to 7/10 supply, so "7 Overlord" means you spawn an overlord directly after your spawning pool.
  From McKay

• With a 6 pool build order you should hit 20 zerglings at 4:05. Put your first 6 on minerals, morph pool asap. Leave the remaining 5. Morph overlord at 100 minerals. Spam zerglings as your larva comes up.

  this works perfectly... tested and completed...

  u start with 6, wait for 200 minerals grab a spawning pool, save up for overlord... grab a overlord (total 2 now for 18 food) u have 5 drones remaining,

  keep spawning zerglings... right after overlord... u will make it in time just nicely...

  From BabyOxide

• Its more to get new players to understand how fast things can be done and to be ready for it ;>

  From Potho