The Marine is back in SC2, with largely the same role and somewhat different stats. Its base HP has been boosted from 40 to 45, and can now be further upgraded to 55 with the Combat Shield.
Additionally, rather indirectly, Marines have been given a power boost because of the new AI and Pathing in SC2. Grouping more efficiently and, due to the fact that SC2 does not take into account shooting through units, means that a large group of Marines can deal damage much more effectively than the Protoss or Zerg tier 1 basic melee units. Marines can also be amassed much more quickly with the new Reactor add-on, which doubles the output of a normal Barracks. However, since the Medic was removed, the only healing available to the Marine (in the form of the Medivac) has been moved up the tech tree.
At WWI 2008, Samwise Didier revealed that players will be able to customize the decals on a Marine's shoulders.
Marines are the first line of defense for most terran worlds in the Koprulu sector. In the time of the old Confederacy the vast majority of marines were criminals or rebels who had undergone mandatory neural resocialization. Freed from any previous allegiances or ideologies, these fearless soldiers stood ready to defend Confederate interests with their lives. The intake of "resoc" marines has been scaled back in many places since the fall of the Confederacy, but remains a common practice, for there are seldom enough volunteers for the job.
The heavy armor worn by marines is effective against small-arms fire and provides them with full life support and NBC (Nuclear/Biological/Chemical) shielding for operation in deep space and other hostile environments. Ballistic alloy combat shields have also been developed in light of experiences during the Brood War, giving an option to toughen up marines faced with an increasingly lethal battlefield.
Marines are normally armed with C-14 Impaler gauss rifles that fire 8mm metal "spikes" at hypersonic speeds. Basic rounds are designed to provide maximum penetration against all armor types, but a number of specialized rounds exist. Of these, the U-238 depleted uranium spike is the most popular because it extends the lethal range of gauss rifles by up to 25%. To preserve ammunition usage and minimize power requirements, the rifle uses a capacitor system to fire in short, controlled bursts. This flexible sidearm can be used to target both air and ground enemies.
If the practice of using resocialized marines has remained controversial, the use of stimpacks is even more of a hot-button subject. These inbuilt chemical delivery systems dose marines with a powerful mix of synthetic adrenaline, endorphins, and a psychotropic aggression enhancer. Marines on stims benefit from greatly increased speed and reflexes, but are subject to long-term side effects including and not limited to insomnia, weight loss, mania/hypomania, seizures, paranoiac hallucinations, internal hemorrhaging, and cerebral deterioration. Nonetheless, both commanders and the marines themselves stand by the use of stims as essential to their continued survival and effectiveness on the battlefield.
| || Combat Shield (C) 
| Minerals || 100
| Gas || 100
| Time || 110
| Researched at || Tech Lab attached to a Barracks
| Affects || Marine
| Increases the maximum hit points by 10. Adds a shield to the Marine's in-game model.