BW ZvT: The Queen Experiment
I just wanted to share some of my thoughts about Queen usage vs. a Terran player going Mech. Veterans will probably know these things, but others might be able to learn something new. My aim is to inform Zerg players about the use of Queens and the Spawn Broodling spell on Tanks and what effect they have on the Terran economy.
The Spawn Broodling spell can instantly eliminate any Terran unit on the ground. Queens can cast it about as far as a Goliath can fire in the air, which means they won't necessarily die after doing so. The most valuable unit to use the spell on is the Tank, which costs a Terran player 150m/100g to build. The backbone of a Mech push is the Tank because of its large damage output (especially with upgrades) and its long range of attack. Rather than using a ground army to engage them, which can be very costly, a Zerg player can use Queens to eliminate them efficiently.
Queens can basically be thought of as tax collectors. Every couple of minutes when a control group of them comes to collect by casting Spawn Broodling on a control group of Tanks, it costs the Terran player at least 1800m/1200g. The reason I say, "at least," is because Broodlings can cause additional damage by making the Tanks splash on themselves and triggering Spider Mines. Artosis famously said that when one is ahead, one should get even further ahead. One way a Zerg player can extend his lead in a game (aside from getting upgrades and tech) is by producing Queens. Queens don't provide any immediate benefit when they spawn, but over the long term they deteriorate the Terran player's economy and army position on the map. It's important that a Zerg player doesn't rely on Queens exclusively; they are supporting units, not replacements for attacking units.
When you are looking to engage a Mech army and have many Mutalisks it's a good idea to cast Spawn Broodling on the Goliaths instead. If you have many Hydralisks, it's a good idea to cast Spawn Broodling on the Tanks.
The Queen Experiment
The Queen Energy upgrade makes a Queen spawn with more energy, which allows it to cast Spawn Broodling sooner. Is it worth investing in this upgrade before the first group of Queens comes into play? Let's find out.
I used a stopwatch to measure the time it takes in seconds for Queens and all their upgrades to complete. The "Fastest" game setting was used.
- Queens take 32 seconds to build.
- Queens without the Queen Energy upgrade spawn with 50 energy.
- Queens with the Queen Energy upgrade spawn with 62 energy.
- It takes 2 minutes and 15 seconds to go from 50 to 150 energy.
- It takes 1 minute and 59 seconds to go from 62 to 150 energy.
- The Spawn Broodling upgrade takes 50 seconds to complete.
- The Ensnare upgrade takes 50 seconds to complete. (This information was unnecessary, but I was curious.)
- The Queen Energy upgrade takes 1 minute and 45 seconds to complete.
Analysis & Conclusions
With these times we can predict how long after a Zerg player decides to use Queens it takes to cast the first set of Broodling spells. Let's assume the Zerg player decides to use Queens in the game at the 15:00 mark.
The reason Queens are built at 16:13 is so that the Queens spawn just as the Queen Energy upgrade completes.
From these spreadsheets we conclude that it's not worth it to get Queen Energy before the first set of Queens comes out. Not only can the resources for that upgrade be used for more important things at the 15:00 mark, but also Terran suffers later rather than sooner.
After an unupgraded Queen spawns, it takes 2 minutes and 15 seconds to kill one tank. This means that the moment a Queen spawns, a Terran player loses on average:
After an upgraded Queen spawns, it takes 1 minutes and 59 seconds to kill one tank. This means that the moment a Queen spawns, a Terran player loses on average:
Therefore, the Queen Energy upgrade increases the rate that new Queens make Terran lose income by about 13.4%. Note, though, that this advantage is lost once the first Spawn Broodling is cast because the upgrade affects the energy the Queen starts with, not the rate that it increases. A Zerg player should get the upgrade if he plans to spawn many more Queens in the game.
After Queens cast their first Spawn Broodling spell at 150 energy, their energy falls to 0. We can determine how long it takes for a Queen to be useful again (to get back to 150 energy) by calculating the rate that it gains energy.
We could also have done (150 - 62)/(60 + 59) and obtained the same result. We have for the Queen recovery time:
Therefore, after a Queen casts its first Spawn Broodling, it takes roughly 3 minutes and 23 seconds before it can cast it again. The rate a Terran player loses from that point on average is:
Questions, comments, and criticisms are welcome. No Queens were harmed in the making of this article. Thanks for reading.