It was unfinished and abandoned when Solokiller began working on his engine overhaul modification. My coder fell in love with his work and after convincing me we decided to let it rest till Solo finishes his project. That was about 2 years ago.
So if you truly are capable of coding yourself.. Feel free to enhance upon it, finish and finalize it.. The whole project was intended to combine the best community made assets into one pack based upon Op4 although we had plans to implement a hud swap changer... Basically allowing you to change the color of the hud to support all 4 major Hl1 games and own universes, white hud, black hud (but it never got implemented) etc..
If you do decide to use it be advised that there were still plenty of bugs or unfinished content in the build.
See my last bug report I committed to my coder internally 2 years ago.https://twhl.info/thread/view/19577?page=1#post-340595
And yes it does work as standalone mod. It's a heavily modified spirit engine with countless bug fixes but also still countless bugs remaining.