Game · FPS & shooters

IO Return to Castle Wolfenstein

Game engine for Return to Castle Wolfenstein.

Completely free
Linux
Open source

At a glance

IO Return to Castle Wolfenstein is completely free: it is open source software, and every feature is available without paying or subscribing.

Its licence (GPL-3.0) is a copyleft open source licence: you may use, study, modify and redistribute it, including commercially; modified versions must keep the same licence.

Strengths

Open source code
Commercial use allowed

About

World War II rages and nations fall. SS head Himmler has Hitler's full backing to twist science and the occult into an army capable of annihilating the Allies once and for all. Battling alone, you're on an intense mission to pierce the black heart of the Third Reich and stop Himmler -- or die trying. The intent of this project is to provide a baseline RTCW which may be used for further development and fun. The map editor and associated compiling tools are not included. We suggest you use a modern copy of GtkRadiant. Some of the major features currently implemented are: SDL backend OpenAL sound API support (multiple speaker support and better sound quality) Full x86_64 support AVI video capture of demos Much improved console autocompletion & Persistent console history Colorized terminal output Much improved QVM tools Many, many bug fixes Commercial data files are required to run the supported games. These can be aquired though a multitude of sources. See the manual for more info on this.

Description from Flathub — AppStream (Flathub)

Sources and checks

Facts collected from Flathub (credit card, source code, publisher, licence, free status, platforms, commercial use, version) — 9 November 2026
Last technical check: 7 November 2026
Description from Flathub — AppStream (Flathub)

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