http://www.joystiq.com/2007/08/02/ma...tion-sickness/
Gamers that played First person shooters in the past without suffering motion sickness is now getting motion sickness from playing the xbl version Marathon: Durandal.
Joystiq.com talked to Freeverse's Bruce Morrison and Buce said First, try playing with the "camera bob" option set to on as the lack of default motion tends to make things appear smoother than they already are. Also, if your mother never told you better, try adjusting your seating position. You may be sitting far too close to your set for this odd, stomach churning experience.
Joystiq.com made the comment "aving taken his advice, we can now enjoy this remastered classic with only a mild headache as the side effect. Thanks, camera bob!"