The game picks up immediately after the ending of Killzone 2 and once again follows the story of the series' main protagonist, Sev, a Special Forces operative fighting for the Interplanetary Strategic Alliance against the Helghast Empire. The game's story has been referred to being similar to the story of David and Goliath. The game continues shortly after Sev successfully defeated and killed Visari, the Helghast dictator who leaves them a final parting gift, detonating a nuclear bomb in the Helghian capital, Phyruss, decimating much of the ISA invasion force. The death of their dictator has left the Helghast Empire in a state of internal struggles with political scheming against each other gripping the Helghast Empire. Now, Sev and his comrade Rico are trapped in the cross-fire between the various political factions in the Helghast Empire without any reinforcements and are left to fight alone in order to escape as the ISA struggles to regroup its forces. The game will also give players a deeper look in to Helghian culture such as their language and showcase whatever humanity they have left within them.
Guerrilla Games has also mentioned that the game's story will be an integral part of the game with dialogue and character development being greatly improved from its 2009 predecessor, In addition, Guerrilla Games has also said that they are curtailing the swearing in Killzone 3, which many felt were unnecessary in the dialogue of Killzone 2. They mentioned that the dialogue in the game should be focused on advancing the story rather than "gratuitous" off the scale swearing without reason.
 Game Play
The gameplay will strongly resemble that of Killzone 2 albeit with several tweaks and changes. Unlike previous games in the series, the game will take place in various harsh environments such as Arctic landscapes, a lethal alien jungle, nuclear wastelands as well as space battles rather than only the city-scape environment which were present in its predecessors. Another notable new feature is the ability to use jet packs in the game, which were seen but unplayable in Killzone: Liberation. The game will also feature a revamped close combat melee system which include new brutal melee attacks as well as the ability to string together multiple attacks in a combo. Unlike its predecessor, Killzone 3 will feature fully destructible environments which is an improvement from its predecessor which featured only partially destructible environments in limited areas. A new weapon called the Wasp has also been revealed, which acts as a multi-firing Rocket Launcher.
 Hardware Info