All artwork, sounds, audio, screenshots, text and code in Natural Selection, Zen of Sudoku, Spark engine and Natural Selection 2 are Copyright © 2014 Unknown Worlds Entertainment, Inc (http://www.unknownworlds.com).

The mark Natural Selection was first represented in association with video-game software in June of 2001, and was first used in commerce around January, 2002. Natural Selection is Registered with the U.S. Patent and Trademark Office (No. 4,179,393).

Uses external code and libraries
- Half Life 1 SDK LICENSE (Copyright(C) Valve Corp.)
- FMOD 3.7.5
- LUA 5.0 (http://lua.org)
- Particle system library by David McAllister (http://www.cs.unc.edu/techreports/00-007.pdf).

Original code and design by Charlie Cleveland (charlie@unknownworlds.com, @flayra).

Many contributions from Karl Patrick (karl.patrick@gmail.com), Petter Rønningen <tankefugl@gmail.com>, Harry Walsh <harry.walsh@gmail.com>, and probably lots of people I forgot.