This is a very fast and easy guide that will cost you just a few steps,you don't need to download mod or hammer of thyrion patch.

-Mouse look
Go to the menu,press Esc,the console screen will appear and then write +mlook,you need to write it every time you open the game otherwise it doesn't work.

1920x1080 Resolution
Right-click Hexen 2,Properties,General,Set launch options and then write -width 1920 -height 1080 -bpp 32

Enjoy