I was experiencing extremely high mouse sensitivity on the X axis (looking left and right) and terribly low sensitivity on the Y axis (looking up and down). I changed the Camera Speed under Gameplay in the Options menu to 0.4 and that solved my X axis sensitivity but it also proportionately worsened my Y axis sensitivity. I was able to solve the problem by editing the ConfigUser.xml file.
Now, there are two ConfigUser.xml files. One of them is in your game installation folder tree, it is simply a template for the other one and editing it will not have any effect on gameplay. The other one is the one that needs to be edited to make changes to gameplay. That one can be found here - "C:\Users\(your name)\AppData\Local\Risen2\Config"
Open that ConfigUser.xml file with Notepad and look for the following entries -
Sensitivity is what we are after. I have excellent results by making the following changes -
As you can see, I set the X sensitivity to the same level that I found to be comfortable by playing around with the Camera Speed under Gameplay in the Options menu. I set the Y sensitivity to five times the X sensitivity, and now my mouse movements feel natural. You may have to experiment to find the perfect alignment for your tastes. Good luck! --- "The choice is not self-sacrifice or domination. The choice is independence or dependence." --Howard Roark