No need to use Vorpx for this.
Follow these instructions: http://www.roadtovr.com/alien-isolation-hidden-oculus-rift-mode-hack-how-to/
If you’re using Oculus runtime 0.7 then type the below into windows “run” to turn off the direct display feature, then launch the game.
C:\Program Files (x86)\Oculus\Tools\directdisplayconfig off
It might take a few tries for it to leave the DK2 screen on before launching the game but it works eventually.