Killzone series

Killzone is a first-person and third-person shooter series of video games exclusively for Sony Computer Entertainment's (SCE) video game consoles. The main series and the PSP installment was developed by Guerilla Games, a subsidiary of SCE. Killlzone currently consists of six games spanning over the PlayStation 2, PlayStation Portable, PlayStation 3, PlayStation Vita, and PlayStation 4. The series began on the PlayStation 2 in November 2004 with Killzone, and continued on the PlayStation Portable in October 2006 with Killzone: Liberation. Killzone 2 was released for the PlayStation 3 in February 2009, and Killzone 3 was released in February 2011 also for the PlayStation 3. Killzone: Mercenary was released for the PlayStation Vita in 2013. On February 20, 2013, Killzone: Shadow Fall was officially announced as a launch title for the PlayStation 4.

Setting
The series is about the galactic war between the Interplanetary Strategic Alliance (ISA) and the Helghast. The Killzone series follows the continuous war between the ISA and Helghast taking place on both ISA Earth colonies and the planet Helghan, the home planet of the Helghast. The series has featured four main protagonists: Cpt/Col. Jan Templar (Killzone and Killzone: Liberation), Sgt. Tomas "Sev" Sevchenko (Killzone 2 and Killzone 3), mercenary Arran Danner (Killzone: Mercenary), and Shadow Marshal Lucas Kellan (Killzone: Shadow Fall). The main antagonist was originally Helghast Emperor Scolar Visari; his death in Killzone 2 brought about the rise of two new antagonists and the hopeful heirs to Visari's throne in Killzone 3: Jorhan Stahl and Admiral Orlock. After Orlock's death and the unknown details of Stahl's death and the destruction of Helghan, now covered in petrusite, the Helghast now live on Vekta with a giant wall dividing them from the Vektans. "The Black Hand", a Helghast paramilitary terrorist group, was formed under Vladko Tyran, who became an antagonist, along with Lady Hera Visari (Scolar Visari's daughter) who has inherited her father's throne. By the end of Killzone: Shadow Fall, it is revealed that the main antagonist is Stahl, who managed to survive the events of Killzone 3. Stahl met his demise by Vektan Security Agency director Thomas Sinclair.

Killzone
Killzone is a squad-based first-person shooter for the PlayStation 2 system. It is the first game in the Killzone franchise. It offered the ability to play the game in four different ways. Helghast Empire has recovered from its defeat in the First Extrasolar War and launched a blitzkrieg against the outer Interplanetary Strategic Alliance (ISA) colony planet Vekta. Vekta's orbital Strategic Defense (S.D.) platforms failed during the initial assault, allowing the Helghast to land swarms of soldiers onto the surface and making it all the more difficult for the outnumbered ISA forces. Captain Jan Templar, the main protagonist, and his squad are called back to the base for reassignment, and are promptly sent to find the ISA operative Hakha and the key in his possession. During the course of the game, Templar meets other characters who assist him such as Shadow Marshal Luger (a female special operations assassin), a heavy weapons specialist Sergeant Rico Velasquez (a Helghast-hating soldier with an itchy trigger finger), and Colonel Hakha, a half-Helghast, half-Human spy.

Killzone: Liberation
This takes place after Killzone but before Killzone 2, it picks up right after the events of the original Killzone. The game was released on the PSP (the portable console) and is the only game in the series which is a third-person shooter. Killzone: Liberation was released for the PlayStation Portable in 2006. In Killzone: Liberation, two months after the events of Killzone, the Helghast have been dealt a hefty blow from the last game, but the war is far from over. The enemy still controls large parts of the planet Vekta, and though the ISA armies are fighting hard, they are losing ground. The rules of war have been cast aside with the sadistic Helghast General, Armin Metrac, employed by the Helghast Emperor Scolar Visari to use brutal measures in order to seize the initiative and strengthen his position further. Jan Templar, returns as the main protagonists on a covert operation to save hostages captured by Metrac, while ISA troops continue the fight for liberty. There are 5 "chapters" with 4 levels in which players eliminate the Helghast resistance (The fifth and final chapter was made available to download).

Killzone 2
This is the sequel to the first two Killzone games and takes place on the planet Helghan. It is the third game involving the Killzone Universe, taking place two years after the original game's ending; this time around, however, it is set on the Helghast homeworld of Helghan, instead of the ISA-controlled Vekta. Sev's unit is deployed behind enemy lines to assist the main invasion force. Tasked with securing the enemy capital of Pyrrhus, Helghan's first true city, the team quickly discovers that the Helghast are a more formidable enemy on their home planet. Not only have they adjusted to Helghan's hostile conditions, they have also harnessed the power of the freakish lightning storms that always occur on Helghan which they can now use against the ISA. A cold, barren, unforgiving world, Helghan provides a ready defense with thick, acidic air, dust clouds, and violent surgical lightning storms. Sev discovers his squad is not just fighting enemy forces—their fiercest opponent may be the planet itself.

Killzone 3
This is the sequel to Killzone 2, set directly after the events of the ending of the game. Killzone 3 is as Killzone 2, exclusive to the PS3. It immediately follows the events of Killzone 2. Visari, the leader of the Helghast is gone, but the war is far from over. Helghast forces have mounted a devastating counterattack, prompting the ISA to smoke out (Interplanetary Strategic Alliance) evacuation of planet Helghan. As new Helghast battalions appear, armed with more powerful weapons, ISA forces find themselves outmanned, outgunned and surrounded. Two new antagonist appear, Jorhan Stahl and Admiral Orlock, who both want to become the new Autarch of Helghan. Sev returns as the protagonist with Rico and Narville.

Killzone Mercenary
Killzone Mercenary is a first-person shooter video game for the PlayStation Vita. Developed by Guerrilla Cambridge, it is the second hand-held title in the Killzone series of video games, and fifth overall. It is the first installment to not be developed by Guerrilla Games directly. The game have players assume the role of a mercenary of Phantom Talon Corp where they will fight alongside either the ISA or Helghast forces depending on which team hires them.

Killzone Trilogy
Killzone Trilogy is a collection of Killzone, Killzone 2, and Killzone 3 for the PlayStation 3 under Sony's PlayStation Collections line. The original Killzone has been remastered in HD to support 720p resolution and Trophies. The collection also includes all DLC maps for Killzone 2 and Killzone 3. It was released on October 23, 2012 in North America.

Killzone Shadow Fall
Killzone: Shadow Fall was released for the PlayStation 4 in 2013. It serves as a launch title and, according to Game Director Steven ter Heide, features "a new world", a new situation and a "new hero". Gameplay and trailer footage reveals that the game is set nearly 30 years after the events of Killzone 3. Vektans now live side by side with Helghans, though their portions of the city are divided by massive walls that are heavily guarded and tensions between the two sides remain high, similar to the Berlin Wall during the Cold War.

Reception
The first Killzone received mixed to positive reviews from magazines and websites. PSM stated that Killzone is "Graphically stunning and hits the mark in so many ways, it's baffling; they promised us we'd experience future war, and we have...and come away shaking." Other reviewers cited technical problems with Killzone, including inconsistent AI, occasional bugs, frame-rate issues, distracting graphical glitches, repetition of the same voices, short draw distance, and an awkward control system. Critics also complained about the gameplay, with IGN labeling it "underwhelming and mediocre" and Into Liquid Sky stating that it needs "more refinement". Sarcastic Gamer's "How to Kill a Brand" (a parody of How to Save a Life) criticized Killzone, saying it didn't deserve a sequel.

Killzone 2 received critical acclaim upon release with a GameRankings score of 90.44%, and a score of 91 out of 100 on Metacritic. Killzone 3 received positive reviews and has a GameRankings score of 86.51%, and a score of 84 out of 100 on Metacritic. The first English review of the game was published by PlayStation Official Magazine (UK), which gave the game a 9/10. The review stated "on a visual level, as a 3D breakthrough, this feels like a watershed moment in a revolution affecting all of gaming". The review also stated on gameplay terms, "Black Ops is the only [first-person shooter] on PlayStation 3 that can match this". The voice acting, however, was criticised as not being perfect, thus lacking "emotive punch" and the reason for not receiving a perfect 10/10.

Killzone: Mercenary has received generally positive reviews with an aggregate Metacritic score of 78/100. The game sold 11,053 copies in Japan within the first week of release. IGN called it "the best portable shooter ever made". TheSixthAxis stated "there’s no other experience like this on a device as small as this".

Critical reception for Killzone: Shadow Fall has been mostly positive. Aggregating review website Metacritic assigned a score of 73 out of 100. It was highly praised for its visuals and multiplayer mode, while criticism was directed at the game's story and AI problems. Although the game is the lowest scoring in the Killzone series, it has still been received as a good launch title and shooter for the PS4. As of January 5, it has sold over 1 million copies (The first 8th generation game to do so) As of March 2nd, it has sold over 2.1 million copies.

Trivia

 * The Killzone series was extended in a comic book by John Ney Rieber and Anderson Garcia. This project was canceled due to Canadian independent publisher Dreamwave Productions going bankrupt few months before the first volume was issued.
 * Killzone: Ascendancy is a novel based on Killzone 3 written by Sam Bradbury.
 * The Helghast share a resemblance to the Kerberos Protect-Gear created by Japanese mechanical designer Yutaka Izubuchi (it's unclear whether the developers at Guerrilla-Games were inspired by Izubuchi's Protect-Gear as basis for the Helghast however, seeming that both designers were rather inspired by Nationalist Socialist Germany and their war machine during World War II)