Genuine valve source spaghetti. There is at least one wall bug left in the game. cp_metalworks_f7 2nd above house/bridge and only on red side. Randomly tested it during a pug when people were talking about it
Blu side valley/underpass texture bug is still there too

They finally patched wallbugs. I tried finding it in the update notes and it's not there. I tried looking in the SDK and after compiling the SDK myself it works there. Somewhere in the proprietary section of the code that's not public, they fixed it

You can still get stuck a little bit but you immediately fall down

I got Venom Crosshairs to work. don't remember how, or if I had any issues getting it to work. All I know it's possible to run under wine

https://github.com/hbivnm/Venom-Crosshairs