Cataclysm: Bright Nights, the fork that kept the modding scene

A fork, and the differences page is the first read

Cataclysm: Bright Nights is a roguelike with sci-fi elements set in a post-apocalyptic world, and it is a fork of Cataclysm: Dark Days Ahead by CleverRaven.

That relationship is stated up front rather than buried, and the README links a page for the differences from its ancestor in the project documentation. For a player, that page is the important document, because a fork means the two games have diverged and any guide, wiki page or mod written for Cataclysm: Dark Days Ahead may or may not apply.

The game itself is described with a little care. The README notes that while some have called it a zombie game, there is far more to Cataclysm than that. The pitch is to struggle to survive in a harsh, persistent, procedurally generated world, scavenging the remnants of a dead civilization for food, equipment, or, if you are lucky, a vehicle with a full tank of gas to get out of there.

The threats are varied: monstrosities from zombies to giant insects to killer robots and things far stranger and deadlier, and against the others like yourself, who want what you have. The endgame framing is that you find a way to stop the Cataclysm, or become one of its strongest monsters.

The project is primarily C++ and the topics cover roguelike, survival, zombies and sci-fi. The last push to the main branch was on 2026-10-19, so it is being worked on daily.

Nightlies, a stable release and an experimental tag

The download section sets out four ways to get the game, and the distinction between them is more interesting than a list of badges usually is.

There is a stable release, a link to the latest stable executable. There is a recent releases page filtered for prereleases, and the release list in the project data shows what that looks like in practice: the most recent tags are Nightly 2026-10-15, Nightly 2026-10-14 and Nightly 2026-10-13, published on consecutive days. There is an experimental release tag, and a Flatpak for the Linux desktop, published as org.cataclysmbn.CataclysmBN on Flathub.

For the source, there is a zip archive of the repository and a clone from the GitHub repo.

So the project ships a stable build, a stream of dated nightlies, and a separate experimental channel. That three tier structure is a deliberate answer to a real problem in a game with an active mod scene: mods are written against a specific version, and a player who runs a nightly and a player who runs the stable build have different games.

The launchers section is where the project draws a hard line, and the wording is emphatic. It states that they do not support any launchers, that none of them are maintained by any members of the development team, and that the vast majority of them do not keep up with the stable release cadence. That is a project deciding that the mod scene it is trying to serve is better served by a mod registry than by a third party downloader, and it is a decision that will frustrate people used to the parent game's ecosystem.

A mod registry instead of a launcher

The answer to the launcher problem is the mod registry at mods.cataclysmbn.org, which the README describes as being used for easier discovery of mods not shipped with the main game.

This is the structural difference between the fork and its ancestor, and it is worth understanding what it does and does not solve. A registry solves discovery. It gives a mod author a place to publish, a player a place to browse, and a maintainer a place to track what exists against a particular build of the game. It does not solve installation, which is exactly the job a launcher would do, and that is why the project can point at a registry and still say it does not support launchers.

The third party mod story is therefore split in two. Discovery and metadata go through the registry, and installation is left to the player, who is expected to know where the game's mod directory is on their platform. The FAQ answers that question in detail, and the answers are per platform, which tells you how much variation there is.

For Windows users it is the game folder, at the same level as the executable, in a mods directory. For Android users using the non-legacy storage it is Documents/Cataclysm-BN/mods. For Linux users using the XDG directories, but explicitly not the Flatpak, it is ~/.local/share/cataclysm-bn/mods. And the general answer for anything else is to boot the game, select help, click 6 for resolved game directories, and place the mods in the folder shown after user mods.

That last step, making the game tell you where its directories are, is the detail that makes the whole thing workable.

Three build paths and a repository shaped like a toolchain

The README keeps building instructions brief and points at three official documents: building with cmake, building with MSYS2, and building with vcpkg. The repository is set up to match, with a CMakeLists.txt, CMakeModules, CMakePresets.json, CMakeSettings.json, cmake-build.bat and cmake-build.ps1, plus a setup.ps1 for the Windows toolchain path.

The top level list shows the scale of the project and the tooling discipline. Alongside the source in src/ there are data/ for the game's data files, gfx/ for the graphics, lang/ for localisation, sound/ for audio, mods/ for the shipped mods, utilities/, tools/, tests/, and android/ for the mobile port. There is a build-data/ and build-scripts/ directory pair, a pre-commit-config.yaml, a.clang-format, a.clang-tidy and a.clangd, an.astylerc, an AGENTS.md, a deno.jsonc with a deno.lock, and a justfile.

The justfile is worth a look, because it shows the routine. Formatting is split into recipes per language, fmt for the whole project, fmt-cpp, fmt-json, fmt-docs, fmt-lua and a separate fmt-return that runs a trailing-return formatting script. Linting is lint-json plus lint-dialogue, and the dialogue linter is tools/dialogue_validator.py run over the NPC data files.

That last recipe is the clearest evidence of what this project is. A dialogue validator over the NPC data means the game has enough branching conversation that a script can check it for errors, which is a level of content tooling that most roguelikes do not reach.

There is also a playtest recipe that downloads and launches a pull request build, run through deno, and a hooks-setup recipe that runs prek install for the commit hooks.

Licensing, translation and the documentation split

The licence arrangement is worth reading precisely, because the README says something slightly different from what the metadata reports.

The contributing section states that Cataclysm: Bright Nights is developed under a Creative Commons Attribution ShareAlike 3.0 licence, and that the code and content of the game is free to use, modify and redistribute for any purpose whatsoever. It then adds the qualification that some code distributed with the project is not part of the project and is released under different software licences, and that the files covered by different software licences have their own licence notices. The repository contains a LICENSE.txt and a separate LICENSE-OFL-Terminus-Font.txt, which is a concrete example of that qualification.

The project licence field is reported as a custom licence that GitHub cannot classify, with a note to see the licence file. This article does not give legal advice, and the practical point for anyone shipping something built on the game's data is that the ShareAlike terms and the per-file notices both apply.

Documentation is split three ways. Gameplay and development documentation lives in the doc/ directory in markdown, the official site is at docs.cataclysmbn.org, and you can build and serve the documentation locally from a guide in the docs directory. The documentation is translated, since the README itself has English, Korean and Japanese versions with matching badges, and the .tx/ directory at the top level is the configuration for that translation workflow.

The community channels are the GitHub Discussions, a Discord server, and an unofficial DDA modding Discord that has a BN channel, which is a good sign for how the fork coexists with the community it came from.

Editorial conclusion

Adopt Cataclysm: Bright Nights if you want the Cataclysm: Dark Days Ahead codebase with a more vehicle and science fiction oriented direction and a registry of mods that are tested against it, because the fork's main advantage is a mod ecosystem rather than a new rules engine. Do not adopt it if you are chasing a stable single player experience, since the default release cadence is nightlies and the project explicitly declines to support third party launchers. Before you install, read the differences from its ancestor in the changelog, since it is a fork and not a patch, and check the licence terms yourself, because the project is under Creative Commons Attribution ShareAlike 3.0 for its own code and content while bundled third party files carry their own notices.

Frequently asked questions

Official sources

1. cataclysmbn/Cataclysm-BN on GitHub
2. Issues
3. Project website
4. README
5. Releases