Play Return to Castle Wolfenstein together in cooperative mode

After my guide to install “iortcw” client for the 2001 released game Return to Castle Wolfenstein, I like to highlight also the “rtcwcoop” project which allows you to play through the missions with your friend(s).

You can grap the client from the project website:

Follow the guide for iortcw for the installation, it is pretty much the same procedure copying the original game date files over.

Have fun.

Return to Castle Wolfenstein – iortcw

Finally found a way to play one of my all-time favorites “Return to Castle Wolfenstein” on a modern computer (and under Linux) with the engine port iortcw. After trying to get the game to run with WINE and PlayForLinux without success, iortcw finally started without any issues in impressive 2560×1440 resolution. Something we only dreamed about back in 2001.

iortcw is an enhanced RTCW engine – id software used to release the source code of all their games back in the day – with some features of the ioquake3 engine. Many features where implemented like the following (from their project site):

  • SDL backend
  • OpenAL sound API support (multiple speaker support and better sound quality)
  • Full x86_64 support
  • VoIP support, both in-game and external support through Mumble.
  • MinGW compilation support on Windows and cross compilation support on Linux
  • AVI video capture of demos
  • Much improved console autocompletion
  • Persistent console history
  • Colorized terminal output
  • Optional Ogg Vorbis support
  • Much improved QVM tools
  • Support for various esoteric operating systems
  • cl_guid support
  • HTTP/FTP download redirection (using cURL)
  • Multiuser support on Windows systems (user specific game data is stored in “My Documents\RTCW”)
  • PNG support
  • Many, many bug fixes

So how to install it? What do I need?

Lets start with what you need:

If you don’t own your copy of Return to Castle Wolfenstein for PC yet, you can purchase it from one of the below links (and support the site, thank you):


  1.  If you haven’t done so, install your original game and remember the target installation directory as you need some game files later
  2. Browse to the iortcw project release folder and grap the latest release files for your operating system. At the point of writing the latest version was v1.51c.
  3. Also grap the latest patch file from this site: This was this file as per now
  4. Extract the latest release zip into a location where you like to have your installation going forward (like c:\Games\ioRTCW\ in Windows or /home/joe/Games/ioRTCW/ in Linux
  5. Go to the location of your existing original installation, go into the “Main” folder and copy the following files over to your ioRTCW “main” folder: pak0.pk3, sp_pak1.pk3 sp_pak2.pk3 sp_pak3.pk3. This is the game date for the single player mod.
  6. Then extract the content of (or a newer version in the meantime) into your iortcw folder and merge its content into it
  7. And that should be it actually: Go to your iortcw installation folder and start either the “iowolfsp*” file for single player or “iowolfmp*” for multiplayer.

I recommend to go straight into the Option menu to tweak the settings for your system and your likening.

Enjoy. Comments appreciated.

Screenshot from one of my favorite levels where you have to escape from Castle Wolfenstein using a cable train: