Why studios continue to use Mouse Acceleration or Smoothing by default is beyond me. It feels like lag. I’d be willing to bet that the majority of people DONT enoy it. This should be an option that is off by default, and you have to turn on.
Anyways, to disable Mouse Smoothing in Dungeon Defenders 2, open the configuration file with notepad or your favorite text editor and change the 4 settings bellow:
C:\Program Files (x86)\Steam\steamapps\common\Dungeon Defenders 2\DunDef2\Engine\Config\BaseInput.ini
Change:
LookRightScale=0
LookUpScale=0