Decision Point (Mass Mutas, Guardians, or Hydra/Lurker)
If you decide to go Mass Mutas:
When Lair is 100%, build 2 Spires and take 2 more gas (totaling 5 gases).
If you decide to go Guardians:
When Lair is 100%, build 1 Spire, 1 Queens Nest, and take 2 more gas (totaling 5 gases).
If you decide to go Hydra/Lurker:
When Lair is 100%, build 1 Spire and take 1 more gas (totaling 4 gases).
Transition
After spending all available gas and larva on Mutas, add 2 Hydralisk Dens and 2 Evolution Chambers for upgrades.
During this time, do not add any hatcheries. Use your resources for Sunkens and Drones.
@ 5-6 minutes, if the enemy has not pressured you, add your 6th Hatchery.
Strategy
The goal is to snipe the enemy's main Nexus/CC/Hatchery by the 6:30-7 minute mark with Mutas.
If you have sustained too much early damage, skip Guardians and focus on building Sunkens for defense.
Tips
Stop spending Larva when the Spire reaches 300 HP. For each 100 HP on the Spire, you'll generate 1 larva. So, when the Spire goes from 300 HP to 600 HP, you'll have 3 larva available per hatchery.
The gas-to-hatchery ratio is important: 1.5 gas per hatchery. This means 1.5 gases can sustain 3 larva production. For 5 hatcheries, you'll need about 4 gases to maintain a 1:1 mineral to gas ratio.
After spending all your gas on Mutas, invest the remaining minerals into Sunkens and Drones.