There's also Doom 3 on the browser: https://wasm.continuation-labs.com/d3demo/

badsectoracula · on March 9, 2022

This is what i was reminded of, but didn't remember the URL.

Sadly main reason i was reminded of it is because the Doom 3 one seems to have better responsiveness for mouselook - the HL version feels a bit too laggy.

(though even the D3 version has a tiny amount of lag which i do not remember when i tried it a couple of years ago - perhaps changes in the browser are to blame)