Resistance

The Resistance is a network of humans and Vortigaunts with the goal of removing the Combine and Wallace Breen from power.

The Resistance
The resistance has no command structure, however there are leaders. Isaac Kleiner, Eli Vance, Barney Calhoun, Arne Magnusson, Judith Mossman, and Alyx Vance are examples of resistance leaders. Gordon Freeman seems to be a person of very high regard for resistance members.

Although resistance members are not always guerrillas with weapons, they can also be simple citizens.

The resistance is mostly present on the Coast, where there are both resistance and Combine bases, and the two factions constantly attack each other. Important Coast bases include Shorepoint, Lighthouse Point, New Little Odessa, and Bridge Point.

The Resistance also holds several large bases (and towns) full of people; these include Ravenholm, Black Mesa East, Saint Olga and White Forest. Black Mesa East and Ravenholm have been destroyed by the Combine, however.

Resistance members who play active combat roles normally wear salvaged Civil Protection vests, green uniforms, or blue uniforms (in City 17).

The Underground Railroad
Citizens of City 17 who choose to escape to Black Mesa East, a very large resistance base, have a very hard time getting there. The only known path is through City 17's canal system, which is subject to frequent raids by Civil Protection officers, hoping to capture or kill any unfortunate refugees, as well as Xenian wildlife such as Barnacles, headcrabs, and zombies. This is how the resistance Underground Railroad was formed.

Resistance members created the Underground, a series of safehouses that help resistance soldiers and Citizens escape to Black Mesa East. Using coordinated safehouses and radios, and an Airboat to lend to refugees. Unfortunately, while Gordon Freeman was moving through the Underground Railroad, most of the stations were tracked down and destroyed by the Combine Civil Protection. Members of the Underground Railroad include Joe and Matt.

Resistance weaponry and technology
Possessing no means to mass manufacture weapons, the resistance don't have standard issue weapons like the Combine forces do. They generally use anything they can find or scavenge from the enemy, so SMG1s, AR2 Pulse Rifles and Shotguns are commonly used. Resistance members are almost always at a disadvantage in combat, being both outnumbered and outgunned by the the better equipped and trained Combine Overwatch forces, along with Combine synths such as Striders and Gunships.

As for technology, the resistance make use of any resources they can find, often building things out of scrap and making specialized vehicles and equipment by hand, such as the Crossbow, Dune Buggy, Muscle Car, and Airboat.

History
The Resistance was formed shortly after the Seven Hour War in response to the Combine takeover. A loose band of guerillas, outlaws and spies dedicated to overthrowing the new world order, they were unable to take on the alien empire directly. So the Resistance instead worked at undermining it by infiltrating the ranks of Civil Protection, smuggling weaponry, setting up a sophisticated underground with bases at Ravenholm, Black Mesa East and White Forest, and by helping civilians escape the Combine controlled cities.

Many of the Resistance's key members are Black Mesa personnel who survived the Black Mesa Incident and the events that took place afterward. Other key members seem to have become leaders due to useful knowledge or experience.

From it's formation until the Combine War, the Resistance mostly operated underground, with safehouses, hidden bases and concealed supply caches in and around City 17. One of the few exceptions to this appears to have been The Coast, where the Resistance had sufficient strength to operate more-or-less openly, with a number bases and outposts, including Shorepoint, New Little Odessa, Bridge Point and Lighthouse Point. Operating from these positions, they regularly sparred with the Combine forces in the area. Over time, though, the Combine made significant inroads into the Coast, destroying many of the smaller outposts and condensing the spread out Resistance forces into larger groups at the main bases. Bridge Point was taken over and occupied, possibly due to the significance of the railway bridge beside it, which the Combine Razor Trains use.

Also around this time, Ravenholm, a secluded mining town connected to Black Mesa East, became one of the main Resistance settlements in the City 17 region, and was home to many escapees from City 17. Upon being discovered by the Combine, the town was subjected to a massive headcrab shell bombardment with only one known survivor. After this disaster, the passage between Ravenholm and Black Mesa East was sealed off.

While some small strikes took place against the Combine, most of the advances that the Resistance made during this time were minor. That would change with the return of Gordon Freeman, who had come to be a figure of legend among the Resistance. Shortly after his arrival in City 17, Gordon made contact with Resistance members Isaac Kleiner, Barney Calhoun, and Alyx Vance. After the teleporter meant to take him to the main base Black Mesa East malfunctioned, he was instead sent on his way through the Underground Railroad network to Black Mesa East. Meanwhile, the Combine, who learned of Gordon's presence when he was accidentally teleported to Dr. Breen's office, launched a citywide sweep to find him, cracking down on the Underground Railroad stations and flooding the tunnels and canals with Manhacks. With many safehouses and stations destroyed or discovered during the crackdown, the railroad disintegrated and most of its members were either killed or captured.

Although Combine forces pursued him every step of the way, Gordon managed to escape and made it to Black Mesa East. But shortly after his arrival it, too, was attacked and destroyed. Eli Vance and Judith Mossman were captured, while Gordon, Alyx Vance and Dog escaped.

Even despite these blows, the Resistance held together, and their hopes were gradually amplified by Freeman's feats against the Combine.

After escaping through Ravenholm, Freeman helped fight off a Combine raid on Shorepoint base and made contact with Alyx Vance. They have learned that Eli Vance and Judith Mossman had been taken to Nova Prospekt, and Alyx resolved to go there and rescue him. Gordon set out along the Coast to reach Nova Prospekt, helping to fend off an attack on New Little Odessa along the way. Finally, he reached Lighthouse Point and joined it's personnel in fighting off a determined Combine attack. Despite their efforts, the base was overwhelmed and presumably destroyed.

After reaching the Vortigaunt Camp, Freeman attacked Nova Prospekt with the help an army of Antlions and, once inside the depot, met up with Alyx Vance, who slipped in by razor train. Fighting their way through the facility, they found both Eli and Judith, but discovered that Judith had betrayed the Resistance and had been working for the Combine. Alyx and Gordon capture Judith and rescue Eli, and intend to use the Combine's teleporter to teleport themselves to Dr. Kleiner's lab. Instead, Judith tricks them and teleports herself and Eli to the Citadel, leaving the two to hold out against scores of soldiers while the teleporter charges up the second time. They manage to teleport themselves to Dr. Kleiners lab, destroying the teleporter and the entire facility in the process. The destruction of Nova Prospekt was the first major victory for the Resistance, and it was taken as a signal to begin the uprising. The Resistance, who had previously only operated underground, engaged the Combine forces in open warfare, with many citizens joining their ranks. This marked the start of the Combine War.

Lasting over a week, The Battle of City 17 was a Rebel victory. The Citadel was destroyed at the cost of City 17, but it cut the Combine forces on Earth off from the rest of the empire. The remaining Resistance forces, having evacuated from City 17 before it's destruction and regrouped at White Forest base, began preparing for the after effects of the Citadel's destruction. The meltdown of the Citadel's core created a superportal, which the Combine would use to bring in huge reinforcements once it had grown big enough. To counter this threat, the Resistance prepared and fired a rocket carrying a satellite which, once in orbit, would close the superportal. The battle to protect the rocket during its launch was furious, and Eli Vance died during it.

Meanwhile, Judith Mossman had discovered the Borealis, which carried Aperture Science technology. A debate raged over whether to destroy the ship or use its technology, and it is unknown which opinion won. Mossman was cut off by Hunter and Elite attacks, and her escort was killed, so Freeman and Alyx journeyed to the Borealis through use of a helicopter to rescue Mossman and decide what to do with the technology.