Alien Swarm
A top-down shooter remake of a mod for Unreal Tournament 2004.
Wikipedia / Wikimedia Commons
Alien Swarm is a multiplayer top-down shooter from Valve, built as a remake of a mod originally created for Unreal Tournament 2004. The same team that made the mod developed the game, and Valve hired them during that process. It came out on July 19, 2010. On April 20, 2017, a group of community volunteers released an enhanced standalone version called Alien Swarm: Reactive Drop, which added new co-op campaigns, a single-player mode with bots, PvP modes, support for up to eight players, Steam Workshop integration, more achievements, and a larger weapon selection. Both games share the same premise: each player controls a space marine in a squad fighting off hostile alien parasites while completing objectives. Critics generally received the game well, praising its gameplay and graphics, though some thought it was too generic. The setting and gameplay were often compared to the 1986 film *Aliens*.
**Gameplay** Alien Swarm is a top-down shooter where up to four players work together in co-op, moving through science-fiction levels and eliminating waves of aliens. Players can choose from 40 equipment options, including assault rifles, grenade launchers, mines, and healing beacons. The game tracks persistent statistics, unlocks equipment, and awards achievements. It is class-based, with roles like Officer, Special Weapons, Medic, and Tech, each offering two characters with distinct abilities. Before a mission, players adjust their loadouts and offhand items. After each mission, they earn experience points, and leveling up unlocks new weapons and items. Missions involve advancing in one general direction, often with multiple objectives. Key points blocking progress are cleared by welding, shooting, or hacking. Meanwhile, aliens called the Swarm attack from all sides, spawning unpredictably and often in large mobs. Different Swarm types have unique behaviors and attack patterns. Players fight them with weapons, explosives, or environmental hazards like explosive barrels.
**Plot** The only official campaign, Jacob’s Rest, is set in December 2052 on a colonized planet overrun by an invasive alien swarm. Marines deployed by the Bloodhound dropship search for survivors and, if needed, destroy the colony to stop the aliens from spreading. The task force kills normal Swarm aliens, eggs, tumor-like growths, parasites, and other creatures. They discover all colonists ha
- Developer
- Valve
- Release Date
- July 19, 2010
- Genre
- Multiplayer top-down shooter
- Engine
- Source engine
- Platform
- Steam (PC)
- Notable Version
- Alien Swarm: Reactive Drop (April 20, 2017)
Lore & Background
Alien Swarm was originally a mod for Unreal Tournament 2004, which won Mod of the Year from GameSpy in 2004 and was a runner-up for Computer Games Magazine's 2004 'Best Mod' award. A Source engine sequel, Alien Swarm: Infested, was announced in 2005 but its development blog stopped updating by late 2007, leaving its status uncertain. In July 2010, Valve announced Alien Swarm, revealing they had hired the original mod team, who finished the game between working on other Valve products such as Left 4 Dead and Portal 2.
The game is class-based, with players choosing from Officer, Special Weapons, Medic, and Tech roles, each with two selectable characters. Up to four players can join a co-operative game, progressing through science fiction-themed levels while eliminating waves of aliens. The game includes persistent statistics, unlockable equipment, and achievements. The only official campaign, Jacob's Rest, is set in December 2052, where marines deployed by the Bloodhound dropship search for survivors on a colonized planet overrun by alien parasites, ultimately guiding a thermonuclear bomb to destroy the colony.
An Alien Swarm software development kit (SDK) with buildable source code was released alongside the game, free to all Steam users. This allowed total conversion mods without relying on content from other Valve games, a significant business decision echoing the Unreal Development Kit. The SDK license permits arbitrary usage and sharing only for non-commercial purposes.
Reader's Guide
Alien Swarm's significance lies in its origin as a mod for Unreal Tournament 2004 that led to the original team being hired by Valve, a notable example of community talent transitioning to professional development. The game itself was a well-received top-down shooter, praised for its gameplay and graphics, though some critics found it generic. Its setting and gameplay were noted as heavily reminiscent of the 1986 film Aliens. The release of the SDK for free to all Steam users was a business decision that encouraged modding and total conversions, similar to the Unreal Development Kit. In 2023, Rock Paper Shotgun listed it among the best free PC games. The later community-developed enhanced version, Alien Swarm: Reactive Drop, added numerous features such as new co-op campaigns, single-player mode with bots, PvP modes, support for up to eight players, Steam Workshop support, more achievements, and an expanded arsenal, extending the game's lifespan. The game's legacy includes its role in demonstrating Valve's support for modding and its continued playability through community efforts.
Did You Know?
- Alien Swarm is a remake of a mod for Unreal Tournament 2004, developed by the original team who were hired by Valve during development.
- The game's only official campaign, Jacob's Rest, is set in December 2052 and involves guiding a thermonuclear bomb to destroy an alien-infested colony.
- An enhanced version called Alien Swarm: Reactive Drop was released on April 20, 2017, by community volunteers.
- The Alien Swarm SDK was released free to all Steam users, allowing total conversion mods without requiring content from other Valve games.
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