Natural Selection 2 is a science fiction-themed multiplayer video game developed and published by Unknown Worlds Entertainment. The game is a sequel to the original Natural Selection mod for the game Half-Life. Natural Selection 2 is a first-person shooter and real-time strategy hybrid. Players take on the role of either aliens or marines, each with different objectives and tactics. Marines must build structures, research technologies, and survive alien attacks while aliens must evolve their species, build hive structures, and attack the marines. The game features a wide range of weapons, abilities, and upgrades for both sides. The game also features a single-player mode, in which the player can play as either the marines or aliens against computer-controlled opponents. There is also a co-operative multiplayer mode, in which players can team up against the computer-controlled opponents. Natural Selection 2 is available for Windows, Mac, and Linux. It is available for purchase on Steam and from the official Natural Selection 2 website.
Dead Space is known for its single player campaign, while NS2 is multiplayer only. NS2 has RTS elements that make it unique among currently available FPS games.
Aliens vs Preditor has no RTS elements like Commander and Base Building in NS2
Doom
Zandronum
Dead Space
Aliens vs Predator
The core element that makes Natural Selection 2 Unique is the RTS part that does not exist in Doom. Also Doom is better known for its sigle player experience, while NS2 is multiplayer only.