Freedoom

Freedoom is a free and open-source project that provides replacement game assets for Doom-compatible engines. Rather than simply recreating Doom's engine—which projects like Chocolate Doom and various source ports already accomplish—Freedoom tackles the other half of the preservation problem: the copyrighted game data itself.

The project provides its own textures, sprites, maps, sounds, music, and other assets, all released under permissive free licenses. This means players can legally download Freedoom and use it with compatible Doom engines without needing to own or provide the original commercial game files.

And despite the name, Freedoom isn't simply "free Doom." It has developed its own visual identity, levels, monsters, weapons, and gameplay content while deliberately maintaining compatibility with the original Doom format. That makes it both a standalone game and an incredibly useful resource for the wider Doom modding ecosystem.

There are multiple Freedoom packages covering different styles of classic Doom gameplay, including Freedoom: Phase 1 and Freedoom: Phase 2, which broadly correspond to the structure of the original Doom and Doom II experiences. You can load them into compatible source ports and experience a full classic FPS campaign without proprietary assets.

The technical side is where things become particularly interesting. Freedoom exists within the enormous ecosystem of Doom source ports and mods, meaning its assets can be experienced through modern engines with features far beyond what the original 1993 game could provide. At the same time, the project remains committed to maintaining compatibility with the old-school Doom format.

That makes Freedoom more than just another free shooter. It is effectively an open alternative foundation for the Doom ecosystem. Developers can build projects around it, modders can use its assets, and players can experience the classic Doom formula without relying on copyrighted game data.

The project also represents something we particularly like about open-source gaming: collaboration over decades. Freedoom isn't the product of one studio trying to recreate an old game. It's a community project that has gradually assembled an entire playable game from independently created pieces.