Adam Z's Notes and Things - Starting a UT2004 Server on Ubuntu 20.04 in 2021 (17yrs later)
PCGamingWiki - Unreal Tournament 2004

UCMP - Ultimate Community Map Pack
CBP - Community Bonus Pack

Runestorm makers of the excellent Ballistic Weapons and JunkWars weapon mods.

Out Of Hell is a total conversion for Unreal Tournament 2004. It is a horror-themed first-person adventure that takes place within Grinwood, an industrial town devastated by a zombie plague.

Found by searching “unreal tournament” on GitHub.

pdinklag/TitanRPG TitanRPG is a complete standalone roleplaying game mutator for Unreal Tournament 2004 based on ideas introduced in UT2004RPG and DruidsRPG. http://dvgaming.com/forumdisplay.php?42-TitanRPG

mattrobenolt/UT2k4-Mods Unreal Tournament 2004 Maps and Characters
abiheiri/UTMaps2004 Unreal Tournament 2004 Maps

When running the Megapack installer from lifl.org you get the following message:

You must install Unreal Tournament 2004 before running this installation program.

The solution is to create the missing symlink ~/.loki/installed/ut2004.xml to /installatiepadut2004/ut2004/.manifest/ut2004.xml:

mkdir -p ~/.loki/installed/
ln -s /usr/local/games/ut2004/.manifest/ut2004.xml ~/.loki/installed/ut2004.xml

After creating the symlink, the Megapack installer can be used.

Source:[Alien Swarm installer] no ut2k4 installed

On an x86_64 system (: add distributions and versions of Linux where this occurs ) you can get the following error when starting ut2004:

Assertion failed: sizeof(*this)==GetClass()->GetPropertiesSize() [File:UnGame.cpp] [Line: 149] 
 
 History: 
 
 Exiting due to error 

This is because the Megapack installer does not replace the ucc-bin and ut2004-bin by newer versions on an x86_64 system.

Run the Megapack installer as follows: sh ut2004.megapack-english-2.run –target /home/username/test

Rename ucc-bin and ut2004-bin in the ut2004 System directory and copy ucc-bin and ut2004-bin from /home/username/test/bin/Linux/x86_64 to the ut2004 System directory (/usr/local/games/ut2004/System).

See also:Trouble with UT2004 megapack

When running the linux-installer.sh script from the mounted CD, the installer asks you to mount the UT2004 play disc.

Open a terminal and su to root, mount /dev/dvdrecorder under /mnt and click on Yes in the window of the UT2004 installer.

Tested to work on: Zenwalk 6.0/6.2, CentOS 6.5, Slackware 14.1 (32-bit).

After installation of UT2004 on Linux in /usr/local/games/ut2004 ut2004 runs, but without sound.
When you start ut2004 from the console, you see the following message:

open /dev/[sound/]dsp: No such file or directory

To fix this, do the following:

• Use Netpkg (Zenwalk) / yum (CentOS, first add atrpms.net repo) / slackpkg+ (Slackware) to install OpenAL.
• Open a terminal and, under the correct user (root?), go to /usr/local/games/ut2004/System.
• Rename the old openal.so:

mv openal.so openal.so.old

• Create a symbolic link openal.so to /usr/lib/libopenal.so.1.6.372 (can be a different version number on your system):

ln -s /usr/lib/libopenal.so.1 openal.so

See also:America's Army forum - sounds not working - /dev/[sound/]dsp

Tested on: CentOS 6.5

Requires:

• Installing compat-libstdc++-33:

  yum install compat-libstdc++-33

• Installing OpenAL:
  • Add the ATrpms repo.
  • Install OpenAL:

    yum install openal-soft

Tested on: Devuan Jessie x64.

Install libstdc++5:

apt-get install libstdc++5:i386 libstdc++5

To prevent the following error:

./ut2004-bin: error while loading shared libraries: libstdc++.so.5: cannot open 
shared object file: No such file or directory

1. Pull down the console with tilde {`/~} (left of 1/! on a US-International keyboard).
2. Enter the setres command with the desired resolution:

   setres 3840x2160

3. Adjust field of view:

   fov 100

   1. Recommended by source:
      1. 100 for 16:10
      2. 106 for 16:9

Source:Steam Community - Unreal Tournament 2004 - How to run this in 4K

Or use GitHub - alexstrout/foxWSFix-UT2k4 for improved widescreen support for Unreal Tournament 2004.