brunys2/halflife — reverse-engineered prompt

Build me a browser version of Half Life from this repo. I want a simple home page where I can choose the main game or Opposing Force, pick English or Russian if those files are available, and then launch it right in the browser. It should feel like a real playable port with a proper loading flow, game screen, audio, fullscreen, mouse capture, and normal keyboard and mouse controls working.

If the actual game assets are not supposed to be committed here, make that clear and set things up so I can drop the files in the right place without guessing. If something is missing, show a friendly message instead of a broken page. Use the images and files already in the project where they make sense, and make the landing page look decent. If there is already support for offline use or installable browser behavior, keep that working too.

Please keep the setup easy so I can run it locally and, if possible, host it as a simple static site. Look up current docs online if you need to.