First Overview of HotS Zerg
Blade was a Grandmaster Zerg player in HotS beta and has written this three part guide. It gives an overview of the early, mid and late game in each match up. Learn also how to best use the new units.
 Blade's Zerg vs Protoss
If you don't already know the basic ZvP openings, the replays included will help you learn. This guide discusses Swarm Hosts, Mutalisk, and Roach/Hydralisk usage and the best ways to use those compositions as well as transitioning into them.
 Blade's Zerg vs Terran
Learn how to deal with the early game Reaper harass, mid game unit compositions, and which units to use in the late game. This section covers Roach/Zergling/Baneling/Swarm Host, and Mutalisk/Zergling/Baneling into Ultralisk. The guide will also cover dealing with drops, Mech units and specific Terran timings.
 Blade's Zerg vs Zerg
This is played very differently in Heart of the Swarm and as such this guide covers all things Mutalisk. The best builds to get them, how to defend yourself waiting for them and how to beat your opponent with them.