Wow! That’s actually such cool news to hear! Thanks for responding so quickly. I will definitely be playing your Portal addon. I’ll be glad to watch the progress continue with this project and am very glad to know such great plans are scheduled for the future.

As of right now, these maps technically aren't compatible with Half-Life 2 (and maybe Half-Life 2: Update, haven't tried that yet), they currently crash the game when you try to load them. But I do know a solution, and once I have every map from Half-Life 2's campaign up here on the workshop, I plan on doing all the background maps too, and turning it all into an addon that has the proper config files needed to make the game not crash. I actually did this with Portal's maps 4 years ago (wow), you can find that addon here. https://www.moddb.com/games/portal/addons/portal-enhanced-shadows-reflections
It might be buggy, I haven't tested it since the last config file patch.

Is there a way to play these maps in main Half-Life 2? I don't know anything about porting GMod maps back to HL2 myself. If these maps are not capable of backwards compatibility right now will you ever make them available to download for HL2 later on? Your work is seriously one of the most impressive modifications of the lighting on the older source games I have ever seen. I'd wait forever to play the full series of HL2 maps if you complete them

For reference, here are my relevant specs:
Ryzen 9 5950x (16 core, 32 thread processor, each core sits at around 3.7GHz when compiling under full load)
64GB of DDR4 @ 3600 MHz

Early on in the HRCS project, I had a Ryzen 5 3600x (a 6 core 12 thread processor) and 32GB of DDR4 @ 3200, and VRAD compiles took at best twice as long, but I didn't do many comparisons before or after upgrading, but with that processor lots of maps took an hour to compile.

Now, a tiny map like d3_c17_01 where I was able to have maximum resolution lightmaps took noticeably longer, with each pass of VRAD taking over 8 and a half minutes, meaning that the final total compile was around 18 minutes, but there were also a lot of "brush lights" (~6500) in that map, as they are influenced by the lightmap scale, and add a lot to the compile time as well, since each light and its bounces have to be included in the already time consuming creation of the super high resolution lightmap.
Speaking of resolution, some of the lightmap scale 1 maps have actually caused my computer to run out of RAM when compiling, which was always fun to deal with, watching the pagefile rapidly grow in an attempt to not bluescreen my computer.

Not sure why I didn't see the first comment, but here's some insight:
This map (d3_c17_06a) actually did not take too long to compile, despite 99% of all surfaces having a lightmap scale of 2 (the second highest resolution, couldn't go any higher on this map due to compile tool/engine limitations), each pass of VRAD.exe (the program that does all the ray tracing for Source Engine maps) took just under 3 minutes, so in total, the final compile took around 6 minutes (since VRAD is run twice for each map, one for standard lighting (LDR) and one for HDR lighting, I also got lucky with this map's geometry and VVIS.exe did a full visibility pass in less than 1 second).

Hellalot of time, I presume. Do you see those shadows? Its maybe 1 or 4 lightmap scale. It will take HELLALOT of time to compile.

how long does it take for you to compile these maps?