Starcraft – When is an appropriate time to transition into Ghosts

For those of you who didn't see the IEM finals they are worth watching.

I've moved the recap down below my explanation

When faced with an early Reaper harass, usually Speedlings plus the occasional Spine Crawler and Queen are sufficient. However, mass Reapers are a very different story.

Mass Reapers usually have speed upgrade putting them at Speedling speed off creep. As a result you need to either get a good surround or engage on creep to win. The natural response to Reapers is Roaches, but without a Speed Upgrade or creep, Reapers are just too fast. Once you have Roach Speed (and can use Overlords to spread creep as Reapers only attack ground) you can usually shut down this mass Reaper play.

Edit: MarroW also suggests throwing down extra Queens, which I think is sound advice. Though the Queens won't help with pursuit, they will help with extra Creep, Transfuse, and longer range if he makes a solid Reaper push. Likewise a Creep Crawler couldn't hurt, but won't help much as once he has 12 Reapers he can almost 1 shot it.

What made it so effect vs Idra was the follow up with Marauders. Based on this its important to prepare for the follow up:

1. Have lots of Creep
2. Banelings, as Marines do too much damage
3. Baneling speed (a lesson Idra learns in Game 1)

Since the ideal build for Marine/Marauder is Banelings followed by Speedlings (or Hydra), as long as you get your Baneling nest out and upgrade speed, you should be in good position to deal with this switch and push on to victory.

There is a good break down of game 3 by Day9 if you want to skip ahead to it.

As for the IEM finals, allow me to give you some context. Marrow (who originally wasn't to be part of the IEM championship but was brought in after BradOK was denied a Visa), plays a very aggressive 5 tech lab vs Idra. Idra is well known as a very passive, very good, zerg player who prefers to fight late game battles with a superior macro style.

In this context, early harassment is a very good strategy against such a passive player as it denies him his economic advantage. In earlier rounds we saw Sarans use harassment effectively vs Idra and pushed him to Game 5 (its a best of 5). So its not unlikely that Marrow studied those matches when he decided on this build.

I want to lay the ground work here so you can see that this was very much designed with Idra in mind.

The build itself revolves around 5 techlabs to push mass Reapers and force Idra to build a lot of Roaches. Ultimately Roaches with speed (or on creep) beat this early Reaper play, but the goal here isn't to win with Reapers, but rather to force Roach production and follow up with a heavy Marauder force (which also require Tech Lab, so your infrastructure is in place).

In game 1, Idra adapts to this change and pushes with a heavy Baneling/Roach/Speedling force, and almost wins. Its worth noting that as Marrow's eventual strategy is MMM, forcing a large number of Roaches gives a very tiny window for victory. What's more, if Idra had Baneling speed upgrade at the time (which he was researching) he would have easily taken out the remaining Marines and pushed on to win Game 1.

In game 2, we see the same strategy again, but with very different results. Idra gets an early Roach speed to shut down Reaper play, and then follows up with Mutalisks to shut down the Marauder push. Marrow makes a good last ditch effort with Ghosts, but ultimately doesn't have the force. Idra decides this fight with Banelings (speed upgraded now).

In Game 3, we see a much more confident Idra who counters the early Reapers with just Roach/Speedling. He'll go on to lose this game much later after a disastrous assault at 12:30, and ultimately get steam rolled by BioMech before he can get more than 2 Ultralisks up.

As Idra strongly believes BioMech is imbalanced vs Zerg, its not hard to imagine a very defeated Idra in Game 4, not playing up to his potential.

There are a number of times when a Planetary Fortress is useful, but before we get to that let's look at what a PF is:

• 150M/150G
• 0 Additional Supply
• 40 AoE damage (20 dps)
• Stationary

The biggest cost of a Planetary Fortress is the lack of building an Orbital Command. If OC wasn't so useful, there is little reason not to build the PF. It has heavy HP and Splash Damage, and doesn't add toward your supply max.

So when does the ability to have an extra Siege Tank worth of damage out weigh the benefit of Orbital Command? Well there is one situation where you have Command Centers in vulnerable positions that may not have quick reinforcements: Expansions. Actually if you watch a lot of high level matches, you'll start to notice that a 3rd or 4th expansion often becomes a Planetary Fortress. Since you're expanding past your natural by the 3rd, you often don't have your army in convenient position. As a result, Planetary Fortress helps to delay attackers and often repel harassment. Ever try to kill a PF with just Zerglings? it ain't pretty.

So next time you're thinking: do I really need a Planetary Fortress? ask yourself this: Do you really need that 3rd expansion to stay alive?