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OpenXcom (X-COM: UFO Defense Open Engine)

Native Linux Turn-based tactics / strategy X-COM: UFO Defense original 1994 (Mythos Games / MicroProse); OpenXcom v2.x 2011–2026 (active) other
Does it run on your Deck?

About

OpenXcom is an open-source reimplementation of X-COM: UFO Defense, the 1994 turn-based tactics and strategic base-management game that became one of the most influential strategy games ever made. Players manage XCOM, a multinational organization defending Earth from an alien invasion, alternating between strategic base management (research, manufacturing, base defense, Skyranger intercept missions) and squad-level tactical combat in destructible tile-based environments. OpenXcom rebuilds the engine from scratch to run on modern hardware while remaining fully compatible with the original game data. It also supports X-COM: Terror from the Deep. The OpenXcom Extended (OXCE) fork extends the engine further with modding infrastructure and gameplay options.

Identity

DeveloperOpenXcom team (SupSuper and contributors)
PublisherOpen source / community release
ReleasedX-COM: UFO Defense original 1994 (Mythos Games / MicroProse); OpenXcom v2.x 2011–2026 (active)
GenreTurn-based tactics / strategy
ModesSingle-player
Engineother
TypeNative Linux
AliasesOpenXcom, X-COM UFO Defense Open Source, UFO Enemy Unknown Open

Launch

Binary
openxcom
Needs files
  • X-COM: UFO Defense game files (cheap on GOG or Steam as 'X-COM: Enemy Unknown')

Runtime

Runs as
Native Linux
Proton
not needed

⚙ Setup notes

Engine: OpenXcom is an open-source reimplementation of the original X-COM: UFO Defense (known in Europe as UFO: Enemy Unknown), the 1994 turn-based tactics and base management classic developed by Mythos Games and published by MicroProse. The project was founded by SupSuper and has been in active community development since 2011.

Proton: No Proton layer is involved — this is a fully native Linux binary. Native Linux builds are available from openxcom.org/downloads/; for the Deck the easiest path is the Linux AppImage from openxcom.org/git-builds/ — mark it executable (right-click → Properties → Permissions → Is executable) and run it. The executable is named openxcom.

Data files: OpenXcom requires the X-COM: UFO Defense data files, which are available very cheaply on GOG (sold under the name 'X-COM: Enemy Unknown') and also on Steam. On Deck, GOG via Heroic Games Launcher is the recommended purchase and download path.

Install: After downloading OpenXcom, copy your vanilla X-COM data subfolders (GEODATA, GEOGRAPH, MAPS, ROUTES, SOUND, TERRAIN, UFOGRAPH, UFOINTRO, UNITS) into a UFO subfolder inside OpenXcom's data or user directory, then launch. Use unmodified data — XcomUtil/modded copies can cause crashes. OpenXcom also supports X-COM: Terror from the Deep: copy its data into a TFTD subfolder using the same process.

OXCE: A popular fork called OpenXcom Extended (OXCE) adds significant additional features: expanded modding support, extended gameplay options, new tactical AI behaviors, many quality-of-life improvements, and a broader base of mods. OXCE is available at openxcom.org/forum and is worth considering as the primary install over base OpenXcom for most players.

Controller: Add as a non-Steam shortcut to access from Game Mode.

The one thing to know

Supply your own copy: Requires X-COM: UFO Defense data files — GOG sells it cheaply as 'X-COM: Enemy Unknown'; use Heroic Games Launcher on Deck to download from GOG. Also supports Terror from the Deep data files for the TFTD campaign.

OXCE: Consider OpenXcom Extended (OXCE) over base OpenXcom — it has more features and the same compatibility.

Controller: OpenXcom uses a mouse-driven UI; set up a Steam Input gamepad layout with right trackpad as mouse for comfortable play.

Community guides

Write-ups and threads from people who got this (or a similar) game running. deckport links to them — it doesn't reproduce them.

Get the artwork

deckport never hosts game images. Open this game on SteamGridDB, pick the cover / hero / logo / icon you like, and drop them into the game folder under .deckport-art/ before you push it to the Deck. The importer files them under the right names automatically.

Run it on your Deck

Two files: the one-time importer (deckport.py) in your Deck's home folder, and this game's install helper. Copy the game into ~/Games and run the helper with Steam closed — it writes the recipe (binary, launch options) and registers the shortcut with artwork.