List of commercial video games with available source code

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Some commercial video games have their source code made public. Developers sometimes share the code to prevent the game from being forgotten, and the code, artwork, and data may be released under different licenses to the public or to communities. The code can appear on public repositories like GitHub, be given to fans, or even be included with the game itself.

Early games were sometimes released as raw source code in languages like BASIC or Python, rather than as ready-to-run binaries. In other cases, source code isn’t available, so fans try to reconstruct it by examining the compiled game. This process is time-consuming and the result is not usually the exact original code—comments and function names are often lost.

The entries about available source code come from unclear releases, leaks, or post-release discoveries rather than official corporate releases. When a company closes or abandons a product, the tools and source code needed to recreate the game are often lost or destroyed (for example, Atari discarded the original sources for many early games).

Rebuilding code from binaries uses methods like decompiling or reverse engineering. A bottom-up reconstruction can produce code that behaves like the original, sometimes even pixel-for-pixel or clock-for-clock accurate, but it is not the exact original source. A top-down approach, by contrast, often recreates a game engine rather than the original code.

Notable efforts include a pixel-accurate reimplementation from 2017 by David Gow, and C99 Keen source code on GitHub under GPLv2, which originally supported Keen 5 and now also Keen 4 and 6.