Here's the timelapse I talked about earlier. This was the real first try. I haven't recorded from the begining and also tweaked it a bit after the end of the timelapse. Wasn't really paying much attention to what I was doing; was just experimenting with the movie features inside zbrush.
About the sculture... well, it was a hard fight in some areas (mouth, especially) but I'm quite happy with the way it turned out. Only around the third minute of the video, when I switch to clay tubes, I start to visualize the shapes and directions of the face... so I guess that's a good tip... when you're stuck and do not really feel the piece, try switching to clay tubes or clay buildup, so you can more easily see what you're doing.