Hi, I have a strange bug where the mouse doesn't work properly with any character. I tried messing with the sensitivity and it doesn't help. It's like the mouse locks to the bottom right, and I can only rotate right. Even if I move the mouse up or down or left, the camera goes right. Any ideas what I can do?

I found a solution, you need to tick a compatibility checkbox!!!
you need to set windows compatibility options for DPI Awareness:
in the compatibility section click "change high DPI settings" and enable "High DPI scaling override" (the bottom checkbox), set it to "application".
after doing this the mouse works!!
Fullscreen or windowed, at native resolution full hd monitor.

extra note: to launch the game properly the first time i had to set also compatibility mode to: "win xp sp2" which will requrie admin to start, after setting video resolution it works also without this checkbox (but it will crash if you go in video options), i also gave "users" full write access to the game directory.

extra note2: you can also use DxWnd program to edit dpi setting, but load the MDK profile (not MDK2 profile!!) and edit it, that software has a bug and config is not saved properly, even if the gui say one thing, the saved file say another)