Like its predecessor, Natural Selection 2 features two opposing teams of players, Kharaa and Frontiersmen, seeking to destroy the other's respective base. While the two teams have the same essential goals, gameplay for each team varies drastically. Marines largely rely on guns and other pieces of technology to annihilate the alien presence. Aliens, however, rely primarily on melee attacks. Certain alien lifeforms can walk on walls, fly, and even dash forward in the blink of an eye. Players also have a currency system which they use to buy better equipment or evolve into higher lifeforms. The primary feature that differentiates Natural Selection 2 from others in the FPS genre is its strategy component. Both teams may have one player act as a commander, who is given a top-down view of the map and plays the game in a Real-time strategy perspective. The commander can place buildings, research upgrades and has a number of abilities to support their team, at the cost of resources. Buildings in Natural Selection are designed to aid players in their offensive, defensive, stealth and speed capabilities. For a team to achieve victory, they must eliminate all of the opposing team command structures. The Aliens also have the option of eliminating all infantry portals and any alive Marines, however because eggs automatically spawn around hives Marines cannot do the same.
Development
A game engine originally dubbed "Evolution" was developed specifically for the game. It has since been renamed "Spark". The game engine utilizes the Lua scripting language for game logic, allowing for easy expansion of the game's mechanics. Physics support is provided by several third-party libraries. The game was officially announced in October 2006. It was to be developed by the Natural Selection creator's newly founded company, Unknown Worlds. Charlie ‘Flayra’ Cleveland will continue his work on the game and Cory Strader will also be contributing concept artwork. On December 1, 2006 the first major announcement of a possible feature was announced, named 'Dynamic Infestation'. A video containing an example of Dynamic Infestation was posted on the Unknown Worlds development blog. On August 31, 2007, podcasts by Max McGuire and Charlie Cleveland were released. These audio updates have since been released at irregular intervals. They discuss the development process, funding and focus, and serve as a basis for interviews with other names in the industry. On April 6, 2008, Unknown Worlds established an office. On July 10, 2008, Unknown Worlds announced their move from the Source Engine to an in-house developed engine dubbed "Spark". Concept artwork was often shown on the Unknown Worlds development blog. In October 2009, Unknown Worlds confirmed plans to support Mac OS X, Linux platforms and perhaps console. However, in February 2010, Max McGuire announced that OS X, Linux, and Xbox support would not be available at the game's initial launch. It was also revealed that Natural Selection amassed over $200,000 in pre-orders and $500,000 through angel investors. On April 9, 2010 a standalone Engine Build became available which included an external map creation utility. On May 7, the Engine Build started using Steam as its primary distribution and update source. On 13 July 2010, Unknown Worlds Entertainment announced that a private alpha was to be released through Steam for all Special Edition pre-order customers on 26 July 2010. It will be updated throughout the game development and eventually become the beta release. The full release version of the game will subsequently follow. The alpha test started on July 26, 2010, with those who pre-ordered the game's "Special Edition" able to activate it via Steam. The game was released on Steam on October 31, 2012. On November 18, 2010, Unknown Worlds Entertainment updated the status from private alpha to closed beta, allowing anyone who had previously pre-ordered either edition of the game, plus the first 10,000 preorders after the announcement was made, into the beta. This was primarily to bring in more capital.
Reception
The game sold 144,000 copies in its first week, earning over $1 million. As of February 26, 2013 the game has sold 300,000 copies. The review aggregator Metacritic shows generally favorable reviews, with a Metascore of 80.
