Cataclysm: Dark Days Ahead (CDDA) is a free and open-source, turn-based survival game set in a post-apocalyptic world. Beginning as a fork of the earlier game Cataclysm — whose source was released by its author in 2010 — CDDA has been developed by its community since early 2013 and now counts more than a thousand volunteer contributors. You wake in a procedurally generated, persistent world that has already ended: scavenge the remains of a dead civilisation for food, tools and fuel, butcher and cook what you can find, build and fortify a shelter, repair or construct a vehicle, and fight — or flee — everything from zombies and giant insects to robots and far stranger things. The game tracks hunger, thirst, morale, temperature, illness, injuries, mutations and bionic implants, and hands you complete freedom over how — and whether — you survive. It ships in two flavours: a text-mode ncurses build and a graphical SDL build with tilesets such as UltiCa. The latest stable release is 0.I-1 “Ito-1” (September 2026), with experimental builds published several times a day.

Key Features

• Persistent, procedurally generated world — every world is generated with its own cities, roads, farms and wilderness, and can be carried over between characters.
• Deep survival simulation — hunger, thirst, morale, temperature, illness and injury all have to be managed, along with seasons, weather and the day/night cycle.
• Scavenge, craft and build — a huge item catalogue to scavenge from the ruins, a deep crafting tree, farming, and base building with construction and fortification.
• Vehicles you can repair and build — dismantle, modify and construct cars, buses and bicycles part by part, or drive away from trouble.
• Character progression — skills, martial arts styles, mutations, bionics, addictions and professions shape your survivor.
• NPCs, factions and non-linear play — work with or against other survivors, trade, recruit, and set your own goals; the game never pushes you along a plot.
• Huge modding support — data-driven JSON content and a mod system you enable per world.
• Text or tiles — play in classic ncurses text mode or with graphical tilesets in the SDL build, with ASCII or tile rendering.

Why Use Cataclysm: Dark Days Ahead?

CDDA is one of the deepest open-source games ever made: an enormous simulated world in which the systems — chemistry, vehicles, weather, injuries, crafting — interlock instead of merely decorating a shooter. It asks nothing in return: no account, no store, no launcher lock-in and no fees, and the whole game and its thousand-contributor content are free to play, modify and redistribute under CC BY-SA 3.0. It also runs almost anywhere, from a netbook or a terminal to an Android phone, and for the technically curious the C++ source is open and heavily documented. Rock, Paper, Shotgun named it one of “The 50 Best Free Games on PC” and later one of “The Greatest PC Games of the 2010s”.

Use Cases

• Playing a deep, turn-based survival roguelike offline at your own pace.
• Long-term base-building, farming and vehicle projects in a world you keep across characters.
• Playing on low-end hardware, in a terminal, or on Android.
• Building and sharing mods or new content for the game.
• Studying open-source C++ game architecture and simulation design.

Platforms

Windows · macOS · Linux (ncurses and SDL builds) · Android (official APK and Play Store build) — also packaged for Debian/Ubuntu, Arch, Fedora and Flathub.

Licence

CC BY-SA 3.0 Unported (Creative Commons Attribution-ShareAlike) — open source.

Website

cataclysmdda.org · source on GitHub

Similar open-source game

Shattered Pixel Dungeon — another free, turn-based traditional roguelike where procedural floors, permadeath and a deep item and equipment system make every run a fresh survival test.