@Ricky: Sound Delay = Gone
Michael Rennie made a change a couple of days ago to either reduce or eliminate the sound delay:
He also added volume control (volume cvar, in other words the volume slider works).
Can't tell you about the input delay, but I'm trying to think of ways that the mouse input can be improved.
Furthermore, although there isn't a Flash 3D API version of this, I may end up trying to port Spike's 24-bit color software renderer in FTEQW to Flash. This would mean that, among other things, a Half-Life type of map could be utilized. (FTEQW's software render is neat, it can even do decals, heh).