I'm actually DLing the game now while i'm at work, but i've been reading lots of stuff that is coming out that people are getting naseous and sick after playing for over an hour. I'm a little nervous, since i do sometimes get sick from FPS.
From the Steam forums, i've heard that the game locks the refresh at 60hz and that forcing this higher helps. I've also heard that disabling vsync may help.
The final thought was that the FOV (field of view) is lower than in many FPS (75 in HL2 vs 90+ in others). Apparently there is a console command that increases the FOV:
This last one seems to have helped a majority of people.
Anyone have this problem?
(BTW, this link has an interesting example of how focal length works: http://www.photozone.de/3Technology/demos/focalCompress.htm