A free, modernized rebuild of the engine that started it all – and an open toolbox for the community that kept it alive. The demo is available now on Steam.

Twenty-five years ago, Arma: Cold War Assault put you on the windswept islands of Everon, Malden and Kolguyev and let you fight a cold war that never quite stayed cold. This is that game’s original “Poseidon” engine, brought into the present: rebuilt in modern C++, configured with CMake and Clang, and running natively on both Windows and Linux (64-bit).

This release is free, and it is two things at once.

A playable demo
A self-contained slice of Cold War Assault you can download and play right now – the classic open-world sandbox, vehicles, AI and mission system that defined a genre, running on a clean, modern codebase.

An official asset pack
The demo doubles as a sanctioned asset pack for the Arma community. The bundled game data is provided as raw material you are free to study, modify and build new Arma content from. If you have ever wanted to learn how a Bohemia game is put together, or wanted clean reference assets to start a mod, this is for you.

Open source
The full engine source code is available on GitHub.

Clone it, build it, study it, and send pull requests. Licensing, developer documentation and the scripting reference all live in the repository.