Vs. Zerg

The 2-Rax Opening is the standard build to punish Zerg players for fast expanding. The possibility of a Bunker filled with Marines is a waking nightmare for Zerg players.

Vs. Protoss

The 2-Rax Opening can transition into a powerful all-in timing attack that sees an army of Marine/Marauders with Stimpack at the front door of your Protoss opponent, or your attack can be used to help secure your expansion as you transition into the late-game.

Vs. Zerg

Knowing whether your Zerg opponent is fast expanding or doing some kind of one-base build (likely 5/7 Roach Rush) is important in setting up your game plan. If the Zerg player is fast expanding, Marines and Bunkers at their front door will back them into a corner for quite some time. But if the Zerg player is not expanding, you will need to use Bunkers defensively for an anticipated Roach Rush/Baneling Bust.

You will want Marines & Marauders against every unit composition a Zerg player can produce in the early to mid-game with the addition of Medivacs to your army during the mid-game.

Vs. Protoss

Early scouting information against Protoss opponents is not as vital as it is in the mid-game to determine the Protoss player’s army composition. As it is against Zerg opponents, Marines and Marauders will make up a large portion of your army against almost any unit composition the Protoss player has in the early/mid-game.

You will eventually add in Medivacs to your army in the mid-game and Vikings to counter any Colossi your Protoss opponent may have added to their army.

Bunker Placement (TvZ)

Against fast expanding Zerg opponents, placing Bunkers right outside the vision of the Zerg’s expansion Hatchery provides you valuable time to complete the Bunker before the Zerg player is even aware of it. 

Timing Attacks

The strength of the 2-Rax Opening is its ability to deliver a powerful timing attack right as Stimpack or weapon/armor upgrades complete. The short period after the completion of an upgrade will give your Terran army a boost that your opponent’s army won’t have.

Transitions

The 2-Rax Opening has many variations to choose from. As discussed, you can choose to use the timing attack to establish your expansion, or go all-in with the hopes of decisively winning the match right there. 

This common Terran build has found its place at all tiers of the ladder primarily for the versatility that it gives the Terran player that uses it. What 2-Rax variation you choose to use is up to you. But there is no question that a Terran player well-versed in the different 2-Rax variations is feared by Zerg and Protoss players alike.