This page covers the progress done after the initial release on this page.
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3257841744
I just haven't find a way to edit it, however I made some progress from the point where the original author left off.

Current version has several significant improvements, in comparison to the initial version:

• NightVision now lights up the environment, and is basically usable.
  
• Custom light sources added to all SP levels excluding bootcamp.
  
• Menu items in video settings are now visible.
  
• In the last level - the rope is moved away to make climbing easier.
  
• Tried to make HUD as bright as possible.

To install - simply restore your Half-Life Steam installation folder, ensure that Opposing Force is also purchased and installed, you can verify it by the presence of 'gearbox' folder at the HL root.
Then download this archive:
https://gofile.io /d/uFbKa5
Password Gabe4Eva!
Place all of three folders:

• gearbox
  
• rt
  
• rt_bin

To the root of Half-Life folder and override any existing files.

Then go to rt_bin and just launch either HL Opposing Force RTX.bat or HL RTX.bat depending on the game you like to play.

Although the game itself is fully completable, there are still some drawbacks that might affect your gameplay:

Allied grunts are terminally stupid in avoiding obstacles.
Some sublevel sections are not culled and are visible in the skybox.
Mounted guns work very strange.

If the communty feedback will indicate some interest in the mod, I think I will try to do Blue Shift as well.

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3257841744
https://github.com/FWGS/hlsdk-portable/tree/opforfixed
https://github.com/sultim-t/xash-rt