Open the file %userprofile%\Local Settings\Application Data\Risen\ConfigUser.xml
Paste the following section into your ConfigUser.xml in the general (option)-Section
* SensitivityX and SensitivityY change your mouse sensitivity, values between 0 and 1 are possible. Don't forget the "f" to indicate that it's a floating point value.
* Set InvertY to "true" if you want your Y axis permanently inverted (the option in the game menu is forgotten after restart, at least in my version). However, you still need to view your options menu once (no changes necessary).
look in the original .xml file for the correct syntax
i had to use in here () instead of <>
[Edited by jackbig, 10/17/2009 2:08:13 PM]