Note: First run the game normally and change resolution – it defaults to 800 x 600 first of all which is very uncomfortable to watch in Rift.
Camera look will only work if you don’t have a gamepad connected (and must use mouse). However I wouldn’t recommend it. It requires you to invert the Y axis for headtracking but trying to do this while the game is running crashes vorpX (and the game flips back to normal mono view mode). Plus the camera is far enough back it doesn’t feel natural to have this linked to headtracking.
Therefore I would either play the game with a gamepad (but have to grab you mouse for edge peek / zoom) or
play with a mouse / keyboard and turn the headtracking off.