Interesting proof of concept, but barely playable as it is.
Shootable buttons aren't. Swimming is broken. Sound has issues when it's turned on. Mouse cannot be moved while holding mouse button to fire, which breaks strafe attacking. Can't change weapons. Can't adjust mouse sensitivity.
If you've never played Quake, do not judge the game by this implementation. The level design and monster placement is the same (in fact it looks very much like they really have taken the files straight from the Shareware release), but there's just too much not quite ready here yet.