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Natural Selection
Natural Selection is the game that established Unknown Worlds Entertainment. Released as a free Half-Life mod on October 31, 2002, it was created by Charlie Cleveland and Cory Strader.
Gameplay
Natural Selection combined first-person shooter gameplay with real-time strategy in a science fiction setting. One player on each team served as the commander, viewing the map from an overhead perspective and placing structures, researching upgrades, and issuing orders. The remaining players fought on the ground as either marines (with conventional weapons) or aliens (with melee attacks and special abilities).
This hybrid FPS/RTS design was unusual for its time. GameSpy called it "possibly the most ambitious user-made modification ever brought to fruition." The commander role added a strategic layer that most multiplayer shooters lacked, and the asymmetric marines-versus-aliens gameplay gave both sides distinct playstyles.
Development and reach
Cleveland was the sole programmer and designer on the original mod, funding development with roughly $40,000 in personal savings. The mod attracted over two million downloads worldwide and logged more than two billion player-minutes of total play time. The community produced extensive maps, balance patches, and a popular sub-mode called NS: Combat that stripped out the strategic layer for pure action.
Natural Selection 2
A standalone sequel released on October 31, 2012, exactly ten years after the original, again on Halloween. Unknown Worlds built a custom engine called Spark specifically for the project, consisting of 250,000 lines of C++ engine code with game logic written entirely in Lua. The engine included a custom Lua IDE called Decoda (later licensed as a separate product) and shipped with a SketchUp-inspired level editor.
NS2 launched at #1 on Steam and reached an all-time peak of 9,510 concurrent players. It sold approximately 300,000 copies. The total development budget was around $2.9 million. Roughly $1.1 million from pre-orders and $1.8 million from angel funding. Cleveland later noted this was about 5% of a typical publisher budget for a game of similar scope.
Development lasted about six years with a core office team of seven people plus remote contractors. Because 95% of game code was written in Lua, the game shipped with all source code accessible to modders. Changes to gameplay could be tested in seconds rather than the 30-minute recompilation times common with C++ engines.
Community Development Team
In 2014, as Unknown Worlds shifted focus to Subnautica, ongoing NS2 development was handed to a Community Development Team (CDT) of volunteer players. In November 2015, Unknown Worlds partially brought the CDT back in-house, hiring eight community members onto a part-time development team with financial compensation.
Postmortem lessons
Cleveland's NS2 postmortem identified the project's main strengths as unstructured development (no producers, no schedules, no design documents), empowered design built around four published design pillars, open community-driven development, and a no-crunch policy.
The key mistake, per Cleveland: excessive scope. NS2 was originally planned as a quick sequel on the Source engine but expanded into a six-year development cycle with a custom engine. He later reflected: "We would have reduced the scope significantly, or made a smaller game, so we could get cash flow positive sooner." The studio nearly went bankrupt multiple times during development.
Current state
NS2 remains available on Steam with a small but active community. Typical concurrent player counts hover between 80 and 180, with two to three servers active during peak hours. The game is no longer receiving updates from Unknown Worlds.
Connection to Subnautica
Natural Selection is relevant to the Subnautica franchise because it established the studio and team that would create one of the most successful survival games ever made. The two franchises share almost nothing in gameplay, but the studio's experience building networked multiplayer for Natural Selection directly informed the co-op features being added to Subnautica 2. Cory Strader, who co-created the original Natural Selection with Cleveland, now serves as Visual Development Lead on Subnautica 2, making him one of the longest-tenured members of the team.