How To Use Terran Units Vs Zerg In Starcraft 2

Essential Units

Marine

Marines are your core units at the beginning of the game when playing versus zerg.They can kill zergling rushes with ease,or put pressure on Queens.When stimmed they can fend of Mutalisk attacks.Avoid using marines against roaches and banelings without proper support from other units or micro.

Marauders

Marauders are basic armored units in the Terran army and as a result they are excellent against roaches,defensive units like spine crawlers or massive armored units like Ultralisks.They are durable units,able to whitstand even baneling damage.Marauders are a nightmare against early zerg when paired with heavy bio counters like Hellions and when stimmed they can raze entire bases of the map.

Hellion

Hellions do enourmous ammounts of damage against bio units,even more when upgraded with the Pre-Igniter.They are a hard counter against Hydralisks and Zerglings and their speed allows them to maneuver arround banelings with ease.They don't stand a chance against armored units like Ultralisks and roaches on their own.The best way to use Hellions is for expansion raids or against heavy Hydralisk/Zergling formations.They are also the best scouts in the game thanks to their movement speed.

Terran Siege Tank

The terran siege tank is essential against any zerg ground formation due to its heavy splash damage in siege mode.When not in siege mode it can quickly attack and dispatch Queens and Roaches,SCV support is recommended.

Secondary Units

Reapers

The reaper is best used early in the game,as an opener.It excells at killing drones and the large attack range and move speed alows the reaper to kite Queens and Roaches.Reapers are very fragile units but in large numbers they can obliterate a base in a matter of seconds.Their high mineral,gas cost and buildtime along with the ineffectiveness against zerg infantry make them a poor choice in mid/late parts of the game.

Terran Ghost

The Ghost against the zerg is valuable due to his Snipe spell against Mutalisks,drones and other organics.He can be critical against zerg players who use Infestors and their Fungal Growth ability.

Terran Thor

When swarms of Mutalisks are present the Thor is viable,but they loose effectiveness as the zerg army grows in numbers.Avoid using thors when Infestors are present as they can use them against your own army.

Terran Viking

Vikings can be used to hunt for Overlords on the map,and can be usefull when Broodlords are on the field.Against Mutalisks and Corruptors they need ground support to be of usefull.

Banshee

The Banshee is a great harasser against all races.With proper micro and the cloak ability you can quickly destroy unguarded Zerg expansions and bases,even take on queens uncloaked.Avoid using them in later parts of the game where Mutalisks and Hydras can destroy them quickly.

Battlecruisers

The Terran Battlecruiser is a great unit against zerg ground forces overall.They can be destructive against Zerglings,Roaches and Hydras when mixed in with the rest of your army.The only thing to avoid when using them is the Corruptor.

Support Units

Medivacs

Crucial support units when playing with a large bio force but can't use the drop ability effieciently due to the speed of the zerg ground force.

Raven

The Raven is a great support unit overall due to the multipurpose nature of their skills.You can use the Point Defense Drones when facing Hydras and Mutaliks,Seeker Missiles against Broodlords,Auto Turrets against Queens and Mutalisk Rushes.The dettection ability of the Raven becomes crucial when burrowed zerg units are present .