Intro

dAImon Keeper is a free, open-source reimplementation of Bullfrog's classic dungeon-management game, Dungeon Keeper. It is derived from KeeperFX (Dungeon Keeper Fan eXpansion), and plays the campaigns and map packs made for it.

KeeperFX began as a decompilation of the original game executables; over the years its entire codebase was rewritten in C/C++. dAImon Keeper continues from that rewritten codebase and focuses on structural modernization: src/ has been refactored from one flat 266-file directory into a set of internal libraries with a strict, enforced dependency graph, the platform layer has moved to SDL3, the build now produces first-class native Linux binaries alongside the Windows build (all driven by CMake), and the game now ships an in-game level, content and campaign editor plus an optional GPU (Vulkan) renderer with dynamic lighting and soft shadows.

dAImon Keeper is a standalone game, but it needs a copy of the original Dungeon Keeper data files as proof of ownership -- it contains none of them. These can be copied from an old CD or from a digital edition (EA, GOG, Steam).

Relationship to KeeperFX

dAImon Keeper is not affiliated with the KeeperFX team and is maintained separately. Please direct issues, questions and pull requests about dAImon Keeper to this repository -- not to KeeperFX's Discord, forums or issue tracker.

For KeeperFX itself, its community and its releases, see keeperfx.net. All credit for the original reimplementation work belongs to the KeeperFX project and the Keeper Klan community (see Acknowledgements and NOTICE).

Compatibility with KeeperFX

• Campaigns and map packs: the version label says which KeeperFX release's content this version plays -- dAImon Keeper 1.0.0 — KFX 1.4 plays content made for KeeperFX 1.4. Content that needs a newer KeeperFX is marked [!] in the level and campaign lists (with the reason on hover), and a level that uses something this version doesn't support says so before play, instead of crashing. Mods still override settings with their own keeperfx.cfg.
• Saves, replays and multiplayer are not shared: dAImon Keeper and KeeperFX refuse each other's saves and replays, don't see each other's LAN games, and dAImon Keeper doesn't use KeeperFX's matchmaking server (online matchmaking is off by default).
• Install it in its own folder: dAImon Keeper has its own settings (daimonkeeper.cfg, seeded once from an existing keeperfx.cfg) and log (daimonkeeper.log), but uses the same fxdata/, save/ and replays/ folders as KeeperFX, whose contents differ between the two games. Keep each game in its own folder; to share files between them (the original game data, campaigns, maps), use symlinks.
• Map editor: saving with Format "Force KeeperFX" writes a map that loads in KeeperFX 1.4 -- it refuses maps that use anything only dAImon Keeper has.

Features

Everything from KeeperFX, including:

• Windows 7/10/11 support
• Higher screen resolutions
• Increased FPS, with graphics decoupled from game logic
• Improved and modernized controls
• Many bugfixes over the original game
• Map, campaign and modding customizability
• Lua scripting for campaigns and maps
• Improved computer-player AI
• Additional campaigns, maps, creatures and other content

dAImon Keeper additionally provides:

• Native Linux builds — a real ELF binary, not a Wine wrapper, portable enough to copy to a machine that never ran the build
• CMake as the single build definition for every target (native Linux, Windows via MSVC/clang-cl, and Windows via mingw-w64 cross-compile), with third-party dependencies fetched and built automatically
• A layered architecture: src/ is split into internal libraries (kfx_platform, kfx_config, kfx_pathfinding, kfx_sim, kfx_render, kfx_net, kfx_game, kfx_frontend, kfx_script, kfx_apploop, kfx_editor) with a one-directional, acyclic dependency graph enforced in CI
• The old ~176-field struct Game god-object broken up into per-library state
• 64-bit clean: long/pointer-width assumptions removed (64-bit integers and doubles throughout, pointer-free state blobs), with a lint ratchet to keep it so
• 32-bit software renderer (no more single 8-bit palette per frame) and an optional GPU renderer (SDL_GPU/Vulkan, selectable under Options → Graphics) with per-pixel coloured dynamic lights, shadow rays and soft shadows
• Dear ImGui front end and HUD: every menu screen is ImGui, plus a reworked in-game sidebar/HUD (classic look still selectable via GUI_ICON_PACK)
• Map Editor (main menu → Tools): terrain, things, rooms, doors, traps, undo, map resize, script and Lua editing with validation, level settings, classic-format and KeeperFX-format save, and one-click playtest
• Content editors: raw config editor, rules, creature, trap/door, spell/ability, room, text/string and campaign editors (new-campaign wizard, levels, land views, speech), with schema validation and a lossless .cfg model
• Skirmish setup tab: per-level rules, availability, win/lose conditions and AI slots, layered over the level's own script
• Frontend/Options-screen and campaign-progress reworks
• Catch2 unit tests per library, alongside the in-game functional tests
• Compatibility checks for KeeperFX content: [!] markers in the level and campaign lists and a warning before play (see Compatibility with KeeperFX)
• External/AI player seats over an in-game TCP API, with an MCP bridge (scripts/llm_bridge/) so an AI assistant can play a keeper

Still in progress or planned: finishing the GPU renderer (depth-buffer rollout, more effects), bringing the modernised HUD further into line with the classic look, and later AI and pathfinding optimisation plus features shown in early Dungeon Keeper previews that never shipped (e.g. hero mode, an AI Keeper with cross-session memory).

Screenshots

Single-screen menu flows

The old multi-screen campaign / scenario routes are now one screen each: pick a campaign or map pack on the left, preview the land or level on the right, enter.

Land selection (campaigns)	Scenarios (map packs)

Reworked sidebar and HUD over the 32-bit renderer (screenshots predate the editors and the GPU lighting work).

How to play

You need the original Dungeon Keeper data files, from an old CD or from the digital edition available on EA, GOG or Steam.

Unpack the dAImon Keeper package into a folder with the original game's files (an existing KeeperFX folder works too), and run daimonkeeper (daimonkeeper.exe on Windows). Which files the game needs from the original release is documented in docs/files_required_from_original_dk.txt; see also docs/daimonkeeper_readme.txt. KeeperFX's GitHub Wiki has general installation guidance and an FAQ that largely applies here too.

Development

The build is CMake-based and fetches / builds its own third-party dependencies (SDL3, OpenAL, ffmpeg, LuaJIT, …), so a machine with just a C/C++ toolchain, cmake, ninja and pkg-config can build end-to-end. It produces one binary, daimonkeeper (the CMake target is still called keeperfx). How much it logs is the Logging option (LOG_LEVEL in daimonkeeper.cfg: OFF, NORMAL, DEBUG or DEBUGMAX), which applies at once.

Linux (native)

Needs gcc/g++, cmake, ninja, pkg-config. Everything else is fetched.

./build-cmake-linux.sh                        # build out/linux/daimonkeeper
SKIP_WINDOWS=1 ./build-package.sh             # full package -> dist/linux/

Windows

Cross-compiled from Linux (this is what CI runs) — needs a MinGW-w64 i686 toolchain (g++-mingw-w64-i686), cmake, ninja:

KFX_OS=windows ./build-cmake-linux.sh                 # build out/windows/daimonkeeper.exe
USE_DOCKER=1 KFX_OS=windows ./build-cmake-linux.sh    # do it in an Ubuntu 24.04 container

Natively on Windows — from an MSYS2 MINGW32 environment with mingw-w64-i686-{gcc,cmake,ninja}, make, git, p7zip, curl, unzip installed:

build-package-windows.bat        REM MinGW build + full package -> pkg\*.7z and dist\windows\

Run it from an ordinary Command Prompt; it boots MSYS2 and calls build-package-windows.sh (which also works if run directly from a MINGW32 shell). It does not do the Linux build or the coverage pass.

• Build details, layout and conventions: CLAUDE.md
• Architecture (authoritative, kept current): docs/Architecture/architecture.md
• Layering check (CI-blocking): python3 scripts/check_layering.py --strict

Tests:

• In-game functional tests: src/ftests/ (run with -ftests) — see src/ftests/README.md
• Standalone CUnit programs: tests/
• Per-library Catch2 unit tests: src/kfx_*/tests/ (KFX_BUILD_TESTS=ON, native Linux)
• KeeperFX content parity: python3 scripts/kfx_parity.py (what KeeperFX has that this tree lacks, and the reverse)

Components

These are resources of the KeeperFX project. dAImon Keeper merges from its game engine and reuses its asset repositories; the dAImon Keeper artwork (icon, start-up screens, banner) is generated from res/branding/.

Component	Language	Info
KeeperFX	C, C++	Upstream game engine.
FXGraphics	-	Sources of KeeperFX graphics files.
FXSounds	-	Sources of KeeperFX audio files.
Masterserver	PHP (CLI)	Multiplayer masterserver for finding public lobbies.
Website	PHP	https://keeperfx.net

Tools

Bundled under tools/, built by the asset pipeline's Makefile rules (build/make/tool_*.mk):

Tool	Usage
po2ngdat	Converts .po files (language) to .dat.
pngpal2raw	Creates a .raw image file usable by the game from a .png and a .pal palette.
fxfontmaker	Builds the in-game bitmap fonts.

Scripts under scripts/ include the layering check, the KeeperFX parity check (kfx_parity.py), and the generators for THIRD_PARTY_NOTICES.txt and the editor's KeeperFX-compatibility list.

Contributing

Contributions to dAImon Keeper are welcome.

• Report bugs by opening issues.
• Contribute code by opening pull requests.
• Run python3 scripts/check_layering.py --strict before adding any cross-library #include.

Acknowledgements

• Bullfrog Productions for the original Dungeon Keeper.
• The KeeperFX project and the Keeper Klan community for many years of work reverse-engineering, rewriting and expanding the game. dAImon Keeper would not exist without it -- visit keeperfx.net.
• The authors of the bundled campaigns and maps, and of the libraries listed in THIRD_PARTY_NOTICES.txt.

License

The program is licensed under the GNU General Public License, version 2 or (at your option) any later version. The graphics are GPLv3 (gfx/LICENSE), the fonts SIL OFL. NOTICE says where dAImon Keeper comes from and what each licence covers; THIRD_PARTY_NOTICES.txt holds the bundled libraries' licences.