I've just set this up on my HTC hero, and it just about worked on the default resolution of 640x480. Turning the res down to 320x240 helped loads obviously, so now it runs a bit quicker. Shame the brightness adjustment in the video menu doesn't work, I can't see anything on my screen unless I'm in the darkest of rooms! The texture quality setting doesn't appear to work either, as that would also boost performance a little. The slider simply doesn't make any difference, and whenever you go back into the options the slider is back at max.
I have two main problems though. The controls aren't good enough to make it playable, as has been suggested it needs the trackball to be allowed for mouselook, using the motion sensor for forwards/backwards and strafing. A sudden shake of the phone would be good for the jump function too. Not sure how we'd crouch though. Perhaps a couple of buttons in the bottom corner of the touchscreen? The same would be useful for changing weapon, as since most of these android phones don't have a physical keyboard we're kind of stuck...
My second annoyance is the lack of cd audio, which is obviously not in the pak file as they were literally just cd tracks on the original release way back in 1997. Could there not be a way of implementing mp3 playback though if I ripped them? The levels were coded so they actually knew which track to play for that particular level, so surely that could be redone with mp3's in place of the cd tracks?