The Faction Pack is the first downloadable content pack for Metro: Last Light, included in the Season Pass. It features three missions set aside from Artyom's journey, but it can be presumed they are canonical.
The levels included are "Heavy Squad", "Kshatriya", and "Sniper Team". Each level is based on a certain gameplay mechanics: shooting, stalking, and sniping respectively. The developer blog for this DLC is here.
The Faction Pack was released on July 16th in North America, and July 17th worldwide. The DLC costs $4.99/£3.99/€4.99, and is included in the Season Pass.
The pack was created with lots of throwbacks to Metro 2033, including locations and enemies, as well as new features and weapons. Several new weapons found in the DLC were previously cut weapons from the main game, such as the Clapper appearing in Sniper Team, and the Hellbreath and Medved (previously a cut underbarrel attachment for the Kalash), both appearing in Heavy Squad. Familiar environments return as well: the Reich outpost at the Black Station returns in Sniper Team; the underground bridge from Frontline returns in Heavy Squad; the Great Library, complete with Librarians, returns in Kshatriya.
While playing as the heavy weapons expert, Hans, in Heavy Squad, the player is tasked with defending the Reich frontline from a massive Red onslaught, holding the line at any cost, armed with the best equipment the Reich can muster, fighting against waves of Red troops, snipers, armoured soldiers, Gatling-gunners, riot shields, and a tank. It's set sometime before the Battle for D6, as the Red Line still have a substantial military.
While playing as the Red Line Sniper, in Sniper Team, the player is tasked with infiltrating a heavily guarded Reich outpost under the cover of a radioactive storm at night, avoiding being spotted, lest you gain an instant failure. A partner accompanies you for a few minutes, but for much of the level you are alone, armed with the powerful yet silent Clapper.
As the Ranger Trainee, in Kshatriya, the player is tasked with searching the Great Lenin Library for rare and valuable pre-war artifacts, as part of their induction into the Ranger Order. Kshatriya is generally more open-world oriented in nature than the other faction missions, having a light role-playing element to it - the ability to trade in artifacts for more gear in order to be able to push the exploration deeper into the library as well as the possibility to manually save the progress that has been made at Polis further sets it apart from them. It also features new ammunition and the return of the terrifying Librarians. It is set during an unknown timeframe.
The Faction Pack has received mixed reviews, with the general consensus being positive. Most agreed that Kshatriya was the strong point of the pack - with its lengthy play-time, new ammunition, and light RPG systems, while Heavy Squad was the weakest - mostly from a lack of context and for such a difficult battle. Sniper Team has also gotten positive reviews for being a solid stealth mission, but like Heavy Squad, also lacks context. Among gameplay commentary, most praised the pack for the amount of content available for such a small price.