Marine (StarCraft)

The marine is the basic infantry unit of terran forces.

The marine is the most versatile tier 1 unit in the game. Compared to the zealot and the zergling, the marine is cheap, is the only one with a ranged attack, and can even hit both ground and air units. They do normal damage, making them useful against all types of armor, and are even more effective in large numbers. StimPacks further increases their effectiveness by greatly increasing their movement speed and reducing their cooldown to almost nothing, at the cost of 10 hit points, enabling marines able to dish out a surprisingly large amount of damage before being killed. In Brood War, medics exponentially increase the effectiveness of marines since StimPacks can be used more liberally, and damage can be healed. Infantry upgrades throughout the game increase the marines, effectiveness by 50%, giving them one of the biggest boosts in the game.

Strategy
Marines are so identified with medics that it's hard to talk about marines without them. Needless to say, in any terran game where marines are expected to be a factor, stimpack should immediately be researched, medics produced, and marine range not far behind. While marine range is not needed to counter any specific units, as compared to dragoon range, it does get marines firing sooner, resulting in a noticeable damage increase. Against zerg, it's standard strategy for the terran to use marines and medics almost exclusively even into the late game. Marines and medics, along with tanks and science vessels, are fantastic at holding a ramp or a chokepoint, and defending against mutalisk harassment alongside missile turrets.

Marines have strategies available throughout the early, mid, and late game. In the early game, a single marine and SCV can start a dreaded bunker rush. If the terran goes supply depot, barracks x2, refinery, and academy, the first medics can assist a very dangerous attack as well. This play is very common against the zerg before mutalisks or lurkers can be produced, with the goal of forcing the opponent to waste money building defensive sunken colonies to prevent off the attack, at no cost to the terran. A siege tank (if you still have time) or additional marines can provide increased pressure against the sunken colonies and threaten a win.

Proxy barracks make these early game strategy faster, riskier, but even more deadly.

Occasionally you will also see marines and bunkers on the defensive. Expensive, usually to buy time. Outranged by static defenses like sunken colony. Stim before entering the bunker. Some players use bunkers in the late game when minerals are plentiful to provide extra chokepoint or base defense. Many players assume when they see a bunker that it is full, even if it is not, so (if you don't show 4 marines waiting to hop in) you can fool them into thinking you have a stronger defensive force then is actually there.

In the mid-game, marines and dropships make incredible harassers.

In late game, marines provide front line defense for tanks and science vessels, particularly in terran vs. zerg matches.

Marines focus fire very well. Know when to attack move and when to focus fire (zerglings vs. hydralisks, for instance). Marines dodge lurker spines, and can split up and surround reavers and tanks.

Counters are heavily-armored units such as battlecruisers and ultralisks, which take little damage from marine attacks. Marines are also vulnerable to units that deal splash damage like lurkers, reavers, and siege tanks and area effect spells like psionic storm. Fast units controlled to execute hit-and-run attacks (Vultures, mutalisks) can pick off marines before they can do much damage, and marines that get surrounded by larger forces have a much harder time unless they focus fire. Zerglings and hydralisks in particular are best used for devastating flanking attacks against marines and medics. But, many times, the zerg player has no choice but to use dark swarm to break a chokepoint.

Against Terran

 * Counters Hard: dropship, missile turret, science vessel, valkyrie
 * Counters Soft: Wraith, SCV
 * Hard Countered by: battlecruiser, irradiate, spider mine, vulture, siege tank (siege mode)
 * Soft Countered by: firebat, goliath

Against Protoss

 * Counters Hard: corsair, shuttle
 * Counters Soft: probe, scout
 * Hard Countered by: archon, carrier, psionic storm, reaver
 * Soft Countered by: disruption web, dragoon, zealot, dark templar, photon cannon

Against Zerg

 * Counters Hard: devourer, overlord, spore colony, scourge
 * Counters Soft: drone, hydralisk, mutalisk, zergling
 * Hard Countered by: guardian, lurker, sunken colony, ultralisk
 * Soft Countered by: dark swarm, ensnare, maelstrom, plague

In the Pro Leagues

 * Boxer, the Emperor, was often considered to be one with his marines. He invented almost all of the techniques with marines known today, and continues to proxy barracks or dropship marine almost every match.
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