I once decided to play Half-Life ray traced, and then of course I wondered if there is the same mod for Opposing Force. I have not found any manual in Steam, and in general on the Internet. Only some bits of information. I decided to dig into this and put it all together. Got the ray tracing with some issues. Why didn't the author of the original mod on HL do it in full, but some noname person could do it, though crookedly? Most likely it was his project for self-presenting, and he don't care about other DLC's. By the way after installing this mod you can play the original HL with tracing as a bonus. Run via Half-Life\rt_bin\xash3d.exe

Before installing, I will strongly warn you that you should not play OF with this mod for the first time in your life. You'll just spoil your impression. Also, you should understand that mod is not working well and don't expect much. I beat the entire game, in some moments with “tricks”

You can download mod from the links below:
just copy and paste this in your browser and delete space

29.10.2025 update: Steam user roflogin has made several patches. https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3595460981
Please use his guide. The information below is outdated.

Mega:
https://mega. nz/file/4N4jxbKL#rfVL-BjdeXgrAr4H8dtPQbWETMPqvOKob1RgE3bsCqs
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mixdrop:
https://mixdrop. is/f/nl6odgzmtrqljj
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pixeldrain:
https://pixeldrain. com/u/wmV9nnVP
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workupload:
https://workupload. com/file/LLq49XqJzNP
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gofile:
https://gofile. io/d/fHMLjA
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1. Install Half-Life
2. Install Opposing Force DLC
3. Unpack folders rt_bin, gearbox, rt, valve to your Half-Life directory. Click "yes" if system ask you to override files.
4. Run the game with Half-Life\rt_bin\HL Opposing Force.bat

You can make a shortcut to this file on your desktop.

My personal recommendations:
• Save more often. F6 and F7 are your best friends
• In particularly dark areas, fire a Glock to light up the room and remember where to go. It has a lot of ammo and it's not a waste. When you get an electric bug (shock roach) with infinite ammo, you can light up the whole room with it. Think of it as a gameplay feature
• Before using "noclip" don't forget to activate "sv_cheats 1" in the console
• In the graphics settings there is an option to enable DLSS or FSR, depending on your preferences

Bugs found by me:
• Missing buttons in the graphics settings. Just know that they should be on the sides of the rectangles with the screen resolution and the DLSS, FSR settings
• Light flickering on walls
• Crashes (lots of them in some places)
• The night vision device only works underwater, otherwise it only illuminates weapons in hands
• On the first boss (Pit Worm) did not work Fire button, although all the valves turned. Flew through with the "noclip" for the boss and passed on.
• At the level "The Package" the game constantly crashed when climbing into the pipe where Otis is sitting. Also, there was a crash at a quick save. How I Resolve it: saved before the garage, passed it until the moment where from the ventilation descend Black Ops guys and at this point with "noclip" flew around the ventilation from the back side, turned off noclip and a little walk back to trigger next level.
• On the final boss (Gene Worm) shoot the portal in the belly with the right gun only. The left one doesn't count for some reason

Answers to possible questions:
• No, there is no way to run it through a library. The xash3d engine that needs for ray tracing is reverse engineered. Valve will never go for even the slightest integration. Exception: add a game as a third party.
• No, you can't get banned because the launch is without Steam. However I do not recommend go to multiplayer. Just to be on safe. Explanation: for any mod that affects the .exe or .dll can get vac when playing in multiplayer.
• Texture mods are likely to work, I have not tried.

I haven't tried experimenting with Blue Shift yet, but the chances of successful are low, since the add-on is obviously weaker than the original game and OF. That means that the community makes niche content. I simply cannot find the libraries client_amd64.dll and hl_amd64.dll in the public. If any of you have experience in compiling in Visual Studio and can find hlsdk for blue shift, then use the information from the guys on reddit (listed below in the links). It shows how to compile the libraries of the original game for x64, so that the engine xash3d normally run them. I will also be glad to have similar files for Gunman Chronicles - it's another my childhood game I would like to try to make better with ray tracing.

https://github.com/sultim-t/xash-rt/releases
https://www.reddit.com/r/HalfLife/comments/11atico/i_have_2_questions_about_half_life_rtx/
https://gamebanana.com/mods/13001
https://www.techpowerup.com/download/nvidia-dlss-dll/