I had much the same experience, and it bummed me out, because I really enjoyed the series. Two things basically eliminated the problem for me- first, like the

I had much the same experience, and it bummed me out, because I really enjoyed the series. Two things basically eliminated the problem for me- first, like the other commenter said, increasing the FOV. The default is way too narrow, especially on modern widescreen displays. Adding another 10 or 20 degrees makes a noticeable improvement. The other change was to eliminate the head-bob while running. There's a console command that takes care of that. Between the two, I went from nausea within a couple of minutes to being able to play for half an hour+ with no issues. Hopefully this helps you, too!