- Hydralisk. More expensive and more dedicated to GtA.
- Roach: Fast regeneration and shorter-range. GtG only.
- Corruptor: AtA unit that turns defeated enemies into stationary AtA turrets.
- Infestor: Can move while burrowed. Can infest buildings, causing them to produce infested units. Has Dark Swarm and Disease (Irradiate for the Zerg)
- Ultralisk: Massive Hp, massive AoE melee damage with a special anti-building attack. Oh, and they can burrow.
- Queen: Unique. Evolves with your Hatchery. Lays Swarm Clutches and Creep Tumors/Shriekers. Has Toxic Creep (causes creep to damage enemies), Swarm Infestation (causes buildings to attack enemies), Regeneration (enhances the speed of Zerg building healing) and Deep Tunnel (teleport to target Zerg building on your side).
- Overseers: Morphed from Overseers. Detectors. Gain greater vision the longer they remain stationary.
- Overlords: Not detectors or transports. Can drop Creep. Has Slime, which allows it to disable resourcing from a mineral patch or geyser.
- Swarm Guardian: Like the Guardian, except its attacks create Broodlings.
Zerg Buildings and Mechanics:
- Nydus Worm. When you create the original Nydus building, you can produce Nydus Worms. These units are always ground units, always burrowed, and can move while burrowed. They can go anywhere. Once they reach a location, you can command them to emerge. At which point, after a few seconds of vulnerability, they become entrances to the shared Nydus network. Units in the network can emerge from any entrance.
- Creep Tumors can be upgraded to Shriekers
- Swarm Clutch: Egg that hatches to attack. Shriekers give them added range.
- Sunken/Spore Clusters: Basically, sunken and spore colonies, except that they don't need Creep Colonies to be built.
- Individual unit upgrades. Rather than having separate +1 upgrades based on unit types, each unit gets its own series of 3 upgrades. These combine the +1 attack/armor for that unit, as well as certain special abilities. The first upgrade for Zerglings, for example, includes their speed. While the last gives them their attack speed upgrade.
- Carrier: Gains the ability to create strong Escorts. Doing so costs money and they take energy.
- Phoenix: Loses AtG attack.
- Archon: Loses "Twilight" prefix and Feedback.
- Medivac replaces Medics and Dropships. It's a DropShip with ranged healing.
- Banshee: AoE attack replaced with single-target damage.
- Thors: now built from Factories.
- Ghosts: Drop Pods cut. Gain the ability to sense units with energy for up to 30 squares.