After playing for about 10-15 minutes the game froze at the beginning of a turn. I didn't do anything special, just pressed "end turn", and the mouse cursor vanished and didn't return after about 4-5 minutes so I rebooted the computer.

I realize that this is probably a totally useless bug report, but I figure that you might be interested to hear anyway, if only to know there's a potential problem.

I'm playing in 1600x1200 resolution, by the way, and another problem I experienced is that the colors are screwed up in all the GNN reports. Maybe this is related.