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X-COM: Terror from the Deep

From PCGamingWiki, the wiki about fixing PC games
X-COM: Terror from the Deep
X-COM: Terror from the Deep cover
Hasbro Interactive
Current 2K Games
Release dates
DOS April 1, 1995
Windows (DOSBox) May 4, 2007
Monetization One-time game purchase
Modes Singleplayer
Pacing Turn-based
Perspectives Bird's-eye view, Isometric
Controls Point and select
Genres Strategy
Themes Sci-fi
Series X-COM
X-COM: Terror from the Deep on HowLongToBeat
X-COM: Terror from the Deep on IGDB
X-COM: Terror from the Deep guide on StrategyWiki
X-COM: Terror from the Deep on MobyGames
X-COM: Terror from the Deep on Wikipedia
X-COM: UFO Defense 1994
X-COM: Terror from the Deep 1995
X-COM: Apocalypse 1997
X-COM: Interceptor 1998
X-COM: Email games 1999
X-COM: Enforcer 2001
XCOM: Enemy Unknown 2012
The Bureau: XCOM Declassified 2013
XCOM 2 2016
XCOM: Chimera Squad 2020

X-COM: Terror from the Deep is a singleplayer bird's-eye view and isometric strategy game in the X-COM series.

Key points

OpenXCom is currently available for TftD, with a new beta build every night.

General information

UFOpaedia - A huge wiki for the XCOM series Community Discussions for game series Support Page
Steam Community Discussions
OpenXCom for a beta build of OpenTFTD, an open-source restoration project.


Source DRM Notes Keys OS
DRM details are not known
Run in DOSBox.
Gamesplanet logo.svg
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Green Man Gaming
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Humble Store
Included in X-COM: Complete Pack, with X-COM: UFO Defense, X-COM: Apocalypse, X-COM: Interceptor and X-COM: Enforcer.
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DRM-free after installation through Steam client (notes may include more details)
GamersGate (unavailable)
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A free demo version is available from

Version differences

The Collectors Edition ("Gold") is Windows-native and, thus, won't run in DOS. It is also pre-patched to version 2.0 and suffers from the same blaster bomb bug (applied to Disruptor Pulse Launcher) as UFO Defense Collector's Edition.[1]

Essential improvements


An open-source, multi platform remake with various improvements.[2][1]
Unlimited save games support, along with native widescreen support and proper audio formats.
DOSBox no longer required, simply copy the new OpenXcom files where the main executable is located or use the provided installer.
Beta builds of TftD are compatible with both XCOM: UFO Defense as well as Terror form the Deep.
New beta builds are released every night.

Original MS-DOS and CE


Patch 2.1 (or 2.0 and the beta geoscape patch) will update the game to the latest. Be sure to apply the 2.0 patch before the beta geoscape one, which is actually the latest patch despite it's name. It should be noted that the CE version and digital versions use the 2.0 patch only. However using the geoscape patch with CE is impossible unfortunately as it replaces the game executable, which it only provides in DOS form.
Run with TFTD Extender plus XcomUtil[3]
TFTD Extender is CE version only. XcomUtil however works on both versions. If you only have the DOS version you can replace some of UFO Extender's functionality with BaseFixer: info on getting Python working in DOSBox is available here and a modified linker for XcomUtil 9.7+ integration can be found here.

The TFTD Extender program runs on the Windows version, providing a mouse-resizable window, a smoother-running, more responsive screen than DOSBox, and a host of fixes for various bugs or exploits in the game.. It also supports the use of higher-quality .mp3 music from the PlayStation release, and keyboard shortcuts. XcomUtil provides bug fixes, including for the disjointed-base bug, and additional ease-of-use features like the automatic re-equipping of soldiers before a mission and appending rank and stat info to soldier names.

Both also offer many gameplay modifications such as enhanced weaponry, different starting-base layouts, and randomized terrain and UFO layouts. These are all optional and turned off by default.

The programs are confirmed to run on Windows 7 as well as older operating systems, and with the Steam release.

XcomUtil supports the TFTDExtender launcher, but assumes the use of DOS or DOSBox at several points in the installation process, so specific steps are required to run them simultaneously:

  1. Install X-COM. If installing from CD, make sure it is a full installation.
  2. Download the UFO Extender loader "", available at this Ufopaedia page, and extract it directly to the folder "TFTD", which is inside the base installation folder (e.g. "Terror from the Deep") in distributions with DOSBox.
  3. In the "TFTD" folder open TFTDExtender.ini, find "D3D=0" and change it to "D3D=1" and change the value of "D3D Windowed" from 0 to 1. Save and close the modified .ini file.
    • On Windows 7 and Vista, you'll only be able to run this mod combo in a window. It will launch work once in fullscreen, and not again subsequently (The window can be maximized though).[citation needed]
    • If you do not wish to install XcomUtil as well, stop here, and you may run the game by launching "TFTDLoader.exe" in the "TFTD" folder.
  4. Download the XcomUtil install file, currently "XcomUtil 9.7 Beta-442.exe", available at the downloads page at Run this file, again directly selecting the "TFTD" folder as the install location. If unavailable, use this .zip file for build 442, extract it into the TFTD folder.
  5. Note that XcomUtil does not officially support TFTD yet so you need to download this mini patch and extract it to the "TFTD" folder and then run XcuSetup.bat. The patch is old so you may have to rename TFTD Extender's exe to "TFTDLoader.exe" for XcomUtil to detect it properly.
  6. XcomUtil setup should now be running in a cmd.exe window. If the cmd.exe screen appears blank, right-click on its title bar and select Properties. Under the Colors tab set "Screen Text" to a contrasting color from "Screen Background".
  7. When asked if you wish to configure XcomUtil now, enter "yes" and allow the program to run.
    • XcomUtil setup may also ask Steam users if they wish to use XcomUtil when X-COM is launched from Steam. However, launching from within Steam will still launch DOSBox instead of the UFO Extender launcher, so select "no". You cannot launch with UFO Extender from Steam's menu.
  8. On the screen that says "Windows 7/Vista has Issues displaying DOS/Win. On startup you get a blank screen..." enter "no" to decline installing the patch suggested.
  9. Enter "yes" when asked if you wish to enable the use of UFO Extender when you launch the game.
  10. Continue answering the rest of the prompts with the options you prefer. If you do not wish to change gameplay, you can still enable the re-equipping of soldiers before each battle with their last set of items, and the automatic addition of useful information to soldier name strings after battles. Info on all the options can be found in the "XcomUtil.txt" file in the "XComUtil" folder.
  11. If you want to change these options, run setup again by launching "XcuSetup.bat" in the "TFTD" folder. You can also do this after starting a game.
  12. You may now launch the game by running "RunXCom.bat" (not "TFTD.bat") in the "TFTD" folder.
    • If you are running Steam do not launch X-COM directly from its menu.
    • Do not run the file "xcomutil.exe" to launch the game. It will not work outside DOS or DOSBox. Xcomutil.exe simply provides a launch menu, with options for running the Xcomutil setup and the X-COM sound programs.
  13. Set additional UFO Extender options as you see fit by altering TFTDextender.ini with Notepad. Information can be found here. In the provided download, all options are off by default, including enhancements that do not affect gameplay. You may enable Geoscape and Battlescape keyboard shortcuts and the stat display on the equip screen by setting the appropriate "Apply" values from 0 to 1, and set the keyboard shortcuts.
  14. To use the enhanced music from the PlayStation version of the game, download the appropriate .mp3 files found here (right-click and select to save the links). Place them together in a new folder inside your XCOM folder. Name the new folder "mp3". Open "TFTDExtender.ini" with Notepad and under the "Music" heading set "Apply" from 0 to 1. Set the track names to match those in the new mp3 folder.


DOS/32A is a more advanced extender and open source replacement to DOS4GW. It can improve both performance and stability of X-COM.

It is recommended to turn off the extender's warning messages with its included ss.exe as they can be rather annoying and show up often when transitioning from geoscape to tactical mode.

Run in DOSBox

To improve DOSBox performance make the following changes to the DOSBox configuration file:

  • Change output=surface to output=opengl
  • Change memsize=16 to memsize=64
  • Change cycles=auto to cycles=auto limit 10000
  • Change prebuffer=20 to prebuffer=10

Force enable videos instead of slides

  1. Copy the ANIMS\ folder from the CD-ROM into the game directory
  2. Create a file called cdspeed.dat and place it in the SOUND\ directory.
Only relevant on a hard disk install of the game (CD installs always use videos). Digital version already have this tweak applied.

Enabling GUS music

UFOPedia has an excellent article on this here.

Game data

Configuration file(s) location

System Location
Windows <path-to-game> (mounted in DOSBox)[Note 1]
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/7650/pfx/[Note 2]

Save game data location

System Location
Windows <path-to-game> (mounted in DOSBox)[Note 1]
Steam Play (Linux) <Steam-folder>/steamapps/compatdata/7650/pfx/[Note 2]

Save game cloud syncing

System Native Notes
GOG Galaxy
Steam Cloud



Keyboard and mouse State Notes
For DOSBox use the DOSBox Mapper (see the glossary page for other workarounds).
Mouse acceleration
Mouse sensitivity
Mouse input in menus
Mouse Y-axis inversion
Controller support
For DOSBox use the DOSBox Mapper (see the glossary page for other workarounds).


Audio feature State Notes
Separate volume controls
Surround sound
Most speech is text-based.
Closed captions
Mute on focus lost
For DOSBox change the priority background value in the DOSBox configuration file.
Royalty free audio
Red Book CD audio
PS1 port only. Tracks can be hacked in on CE with UFO Extender.
General MIDI audio


Language UI Audio Sub Notes
Use the 8 in 1 Language patch, available for CE here
Standalone patch also available here
Use the 8 in 1 Language patch, available for CE here
Use the 8 in 1 Language patch, available for CE here
Use the 8 in 1 Language patch, available for CE here
Fan translation by «Бюро переводов Old-Games.Ru»


Multiplayer types

Type Native Players Notes
Local play
2 Versus
Hotseat. Requires XcomUtil; a tutorial explaining the process can be found here. A batch to simplify the process can also be found here (direct link).
LAN play
2 Versus
Use the above method, but also requires passing save files around via sneakernet (physical media)
Online play
2 Versus
Same as above, but use email instead of sneaker net.

Issues fixed

Almost every single major bug has been fixed in OpenXcom.

Research tree bugs

The Research tree bugs can generally be fixed by using TFTDExtender of XcomUtil. If you are reluctant to use these you could try the TRTBAG instead.

No music when attempting to play digital versions of CE

Some digital versions of CE shipped without their MIDI sheet. Copy these into the sound\ directory.

Other information


Technical specs Supported Notes
DOS video modes VGA SVGA compatible.

System requirements

Minimum Recommended
Operating system (OS) 5.0
Processor (CPU) Intel 386 33 MHz
System memory (RAM) 4 MB
Hard disk drive (HDD) 60 MB
Video card (GPU) VGA


  1. 1.0 1.1 File/folder structure within the installation folder reflects the path(s) listed for DOS game data. For the release, file changes in DOSBox are redirected to <path-to-game>/cloud_saves/ even if GOG Galaxy is not used (this folder contains all redirected files, so some files in the cloud_saves folder might be temporary files or other files that do not contain saves or settings).
  2. 2.0 2.1 File/folder structure within this directory reflects the path(s) listed for Windows and/or Steam game data (use Wine regedit to access Windows registry paths). Games with Steam Cloud support may store data in ~/.steam/steam/userdata/<user-id>/7650/ in addition to or instead of this directory. The app ID (7650) may differ in some cases. Treat backslashes as forward slashes. See the glossary page for details.