Half-Life 2 (stylized H λ L F - L I F E ²) is the canonical sequel to the series hit Half-Life, released by Valve Software. The game takes place 20 years into the future after the infamous Resonance Cascade at Black Mesa, which ripped a hole in the universe and allowed the creatures of Xen and the attacking force known as the Combine to enter Earth's atmosphere and begin a new era with a new order of control for the Combine. The game revolves around Gordon's adventures in City 17 as his return marks the beginning of a rebellion against the oppression of the citizens. The game takes place over the course of three days, and a week.
During Half-Life 2's development in 1999, it was planned that the game was going to be released for the Source engine. It started off as a fork of the GoldSrc engine and the first screenshot publicly available dates back to the original Get Your Free TV's demonstration, which was used to show advanced scripting abilities that the engine could handle. The engine focused a lot on features to enhance the game that was never seen in the previous engine. For instance, the engine is capable of using an enhanced lighting system to make it more realistic, the game uses cubemaps to emphasize the details of textures such as the ground and objects, facial expressions, and even physics.
During the development of the game engine, Valve had also planned to port a few GoldSrc games over to the new engine, such as Half-Life, Counter-Strike, and Day of Defeat. The point of the Source ports of these games was to compare the Source engine to GoldSrc engine releases.
During Half-Life 2's development, many chapters were cut from the game. Some would make a return in other games, while some were planned for another game but was cancelled ultimately. Some were planned to not make a return since it has no room to be canon. These cut chapters of the game were a result of Marc Laidlaw joining the project later on in development.
In the original Half-Life 2 story, Gordon Freeman was sent to visit an area quite a ways from City 17, known as the Arctic. Here, he would use the Ice Axe, a cut weapon, to dig in the ice to find the Borealis. This chapter was cut due to not being developed and due to the next chapter that would have kept this chapter relevant being cut as well.
It may have been planned to return in Half-Life 2: Episode 3 when Gordon and Alyx were planned to ride in a chopper to reach the Arctic region.
Hyperborea / The Borealis
This chapter was used to originally help Gordon get to Kraken Base but would have been infiltrated by the Combine, forcing Gordon and Odell (a cut character) to flee the ship under attack. The chapter was planned to be shown off at E3 in the year of 2002, however the showing for Half-Life 2 was cancelled and the map was never shown off. The map is named
e3_ship. Alternatively, a devtest of the map exists from late 2001 to test the engine's capabilities which took place on the Borealis.
The chapter was also planned to return in Half-Life 2: Episode 3, however instead of the ship being used to transport rebel citizens to Kraken Base, it would have been used to return Gordon back in time with hopes to stop the Combine.
Air Exchange and Weather Control
Air Exchange is chapter that featured a factory that was causing the air to be polluted and irradiated in the original storyline. The chapter revolved around Gordon Freeman turning off the factory to prevent the air from being polluted and caused the air to become restored. Weather Control was a chapter that followed but unfortunately does not have much data known about it, with almost no maps existing for this section. These chapters were cut however since the game was planned to have non-polluted air and non irradiated skies.
Quarry was originally used in place of the Water Hazard chapter of the retail game. It would lead into the area commonly known as Ravenholm, but during development was Quarry Town. It was meant to be traversed by Gordon on foot likely before reaching the town.
Vertigo / The Palace
Vertigo or The Palace takes place when Gordon and Alyx are flying a chopper, it's attacked by the Combine, and crashes into an office tower. The entire chapter was about Gordon escaping the tower and taking on groups of the Combine. Since the chopper ride did not happen in the retail game, this chapter would have had no relevance to the story. It was replaced with the chapter Follow Freeman. The chapter would have originally led into the street wars chapter, which was known in the retail game as Anticitizen One.
Lost Coast was a chapter that canonically would have taken place after Highway 17. It involved Gordon Freeman meeting up with a fisherman who talks about what has become of the bodies of water on Earth and finally asks for your help to eliminate the Combine. The chapter, while short, was likely a late addition but scrapped from being canonical since it was not vital to the story line.
In 2005, one year after Half-Life 2 released, Valve Software released a demo called Half-Life 2: Lost Coast which featured HDR support for the engine and other additions that would be incorporated into the Episodes. The demo can be played on Steam via acquiring Half-Life 2, or buying the game when it was possible to buy the demo seperately.
Half-Life 2 was set to originally release September 30, 2003, months after the E3 presentation from 2003. The game to many fans' disappointment was delayed to some time in 2004. Around the time of the original release, Valve Software was breached and a great chunk of the Source Engine's source code, along with projects and various files were stolen by someone living in Germany. The leak was big news as the leaker and their friends had leaked the game on torrents a week after the hacks.
Half-Life 2, along with Half-Life: Source, Counter-Strike: Source, Team Fortress 2, Counter-Strike: Condition Zero, and a number of other files were stolen from Valve. Other files such as nVidia's Detonator game driver and development maps for both Half-Life source games were also stolen.
In 2004, the hacker made contact with C.E.O. Gabe Newell at Valve, claiming he was the hacker and sent a file that he purposely excluded from the leak to prove his legitimacy. Valve had planned to offer the hacker a free tour of the offices and a job to work at the company to lure him into a trap that would allow the F.B.I. to legally jail him when travelling to America. The German government however caught on with what was happening and decided to arrest the hacker before he could follow through with the bait plans.
Half-Life 2: Survivor
A Japanese exclusive arcade cabinet was developed by Valve in conjunction with Taito after the game's release. The game consisted of a single player mode which was a puzzle-less playthrough of snippets of the Half-Life campaign and a multiplayer mode which was a specialized version of Half-Life 2: Deathmatch. The binaries for the arcade cabinet have been discovered and were dumped for the public to view. Since the arcade cabinet was running on a standard Microsoft Windows install, running it on PC required no effort to achieve.
Half-Life 2 has had two major re-releases since its initial launch in 2004.
Orange Box Re-release
Half-Life 2 was re-released when the Orange Box was published in 2007. The Orange Box was published for PC players to play as well as Playstation 3 and Xbox 360. The re-release included minor bugfixes to the game as well as making a few cosmetic changes to enemies. The game's engine was updated on PC again 4 years after which became known as the Steampipe update, which made the game become the Steam version but consequentially caused mods to break.
nVidia Game Shield
Half-Life 2, along with the Episodes and Portal was re-released for the nVidia Game Shield, some time in 2015. This was the official port for Android platforms and sold for the same amount as it is listed on Steam for PC players. The original release of the four games all had accidental developer maps included in the data files to test the game engine and ensure the port is suitable for public use.
After the release of Half-Life 2, the physics gun that was usable in the leaked build inspired Garry Newman to create a mod for Half-Life 2 that would be primarily focused on this gun. This led to the creation of Garry's Mod, which is Half-Life 2's equivalent of Sven Co-op. The mod would go on to be popular enough to eventually catch Valve's attention which offered Newman an opportunity to list his game on Steam. To this day, Valve has given Garry access to Source 2 to create a new successor for Garry's Mod, which became known to be S&box.