

Marines are the most physically frail of the species and are therefore the easiest to kill. Marines are not as numerous as Aliens, but they are typically far more numerous than Predators. Every Marine combatant is capable of attacking at range, and many of their weapons can damage small groups of enemies simultaneously. Marines can deliver the most concentrated firepower of any of the species. These forces are immune to a number of side effects, including radiation, acid scarring, virulence, spores, cysts, and bleeder spears. Marines have a variety of robotic and mechanical troops and equipment, including the Synthetic, Sentry Gun, ExoSuit, and the Atmo. The Synthetic can additionally detect and highlight moving objects outside of its standard visual range, and the upgraded Sentry Gun has the ability to respond to ranged enemies attacking from beyond its field of view. The USCM can detect cloaked Predators with the Synthetic or the Sentry Gun, both of which are equipped with cloak-defeating sensors. Healing and repairing are free, but a given Medic or CommTech can only heal or repair one target at a time, making the process somewhat time-consuming. They can use the CommTech to repair robotic and mechanical troops and equipment, including the Synthetic, Sentry Gun, ExoSuit, and the all-important Atmo. Marines can heal their organic forces with the Medic. Accordingly, Marine detachments must ensure they maintain sufficient force levels to secure subsequent Atmos and complete their mission.


There are a limited number of Atmos available during each mission, each of which provides a fixed sum over its lifespan. Marines can earn credits in two ways: 1) they can repair Atmos with a CommTech and receive a continuous stream of credits while the Atmo remains operational, and 2) they can receive a small bounty for each slain enemy.

Naturally, there is a small amount of transit time before reinforcements arrive. He does this by calling a dropship down on whatever visited dropship beacon is nearest his current location. The USCM orders reinforcements and field upgrades via the CommTech Marine.
