Developer and game mechanics documentation for OpenApoc, the open-source C++17 reimplementation of X-COM: Apocalypse (1997).
This repository is included as a git submodule in the main OpenApoc project under the wiki/ directory.
Reference documentation for the original X-COM: Apocalypse mechanics, useful for developers implementing or verifying game systems.
- Combat System — Real-time vs turn-based, damage types, weapons, armor, shields
- Psionics — Psi mechanics, stun, panic, mind control, psi-energy
- City Management — Mega-Primus, organizations, diplomacy, alien infiltration
- Vehicles — Vehicle types, UFO types, aerial combat stats
- Agents — Agent stats, training, types (human/hybrid/android)
- Research & Manufacturing — Tech tree, dual research branches
- Base Building — Facilities and base construction
- Aliens — Alien species, ecology, the alien dimension
- Scoring & Difficulty — Score calculation, funding, dynamic difficulty
- Known Bugs — Documented bugs in the original game
- Cut Features — Features planned but cut from the original
Documentation specific to OpenApoc's additions and changes.
- New Features — All 54+ configurable gameplay options
- Controls — Full control scheme with improved city controls
- Modding — XML data, Lua scripting, mod loading, save editing
- Debug Mode — Debug hotkeys and cheat system
- Notifications — 38 configurable pause notifications
- Roadmap — Development status and milestones
Side-by-side analysis of original vs OpenApoc.
- Differences — Comprehensive list of differences
- Bug Fixes — Original game bugs that OpenApoc fixes
- Shared Mechanics — Mechanics that work the same in both
Developer-focused documentation for contributing to OpenApoc.
- Architecture — High-level codebase architecture
- Building — Build instructions for all platforms
- Data Formats — XML data format reference
- Forms UI — Forms UI library and XML control reference
- Coding Style — Code style guide and conventions
Documentation of the AI-assisted research process that produced this wiki.
- Research Statistics — Metrics and scale of the documentation overhaul
- Discord Mining Summary — 20 critical findings extracted from 77,612 Discord messages
- State of OpenApoc 2026 — Comprehensive project status assessment
- Future Works — Checklist of actionable next steps
- Links — External references, community links, useful URLs
This wiki is included as a submodule in the OpenApoc repository:
# Clone OpenApoc with wiki:
git clone --recurse-submodules https://github.com/ayrtondenner/OpenApoc.git
# Or initialize after cloning:
git submodule update --init wiki
# Update wiki to latest:
cd wiki && git pull origin main && cd ..
git add wiki
git commit -m "Update wiki submodule"Contributions are welcome! Please submit pull requests to this repository. See CONTRIBUTING.md for guidelines.
Player-facing documentation is maintained on UFOpaedia.
GPL-3.0 — matching the OpenApoc project.